Toward A More Comprehensive Keyless Entry DIY

E28 technical advice asked and given! Troubleshooting, modifications and more.
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davintosh
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Toward A More Comprehensive Keyless Entry DIY

Post by davintosh »

So there are several threads on this site (and others) with information on wiring up an aftermarket keyless entry system on an e28. It is hands-down one of the best -- and easiest -- mods there is for our cars! Some of the threads are a bit aged though, and some of the photo links in those threads are dead, plus I found that the unit I bought had totally different color coding on the wires, so while the other threads were somewhat helpful and encouraging, I didn't find one that was a straight-up how-to for the unit I bought.

So I did some homework on the job as if I were starting from scratch; read up on how the e28's central locking system works and worked out what the keyless remote unit does and how should interface with the e28's locking system. While the install isn't terribly difficult (and the existing threads helped a lot!) it was kind of fun to puzzle through the process. Afterwards I thought I'd put together a DIY to share what I learned. Looks like it ended up being a little wordy (entschuldigung!), but it should be reasonably thorough. If not, that's what the comments in the thread are for!

Of course, modifying your car to make use of a keyless remote system assumes a couple of things; first that your car is equipped with a central locking system, and that said central locking system actually works. If your car doesn't have one, or it doesn't work, then this might be an interesting read, but probably not very helpful for you.

Next, determine which keyless remote system you're going to use, and buy it. There are lots of systems available, and many are priced pretty reasonably. I just shopped around online for a somewhat simple universal system that had a decent number of reviews and a reasonably good rating, and was happy with what I got. Amazon and eBay are good places to shop. There's also a JC Whitney item that several others have installed and are happy with; more info that one here. I don't think there's much reason to spend more than $20 on one; I purchased mine on Amazon.de for about 15 Euros, and while it can do a couple more tricks, all I want it for right now is to lock & unlock the doors, trunk, & fuel filler door without a key.

The remote units (boopity boops!) included with my system have four buttons; lock, unlock, flash the lights, and pop the trunk open. The trunk thing I have no need for, so that button just won't get used. I may expand my installation later and hook up the tail lights for the flashy thing.

Image

The next step is to figure out how to get yours to work with the e28's central locking system. The Bentley manual for the e28 has some schematics in it, but isn't nearly as helpful in figuring out the system as the ETM (Electrical Troubleshooting Manual). The schematics can be a little difficult to read if you're not familiar with electronics, but the description is very helpful:
Lock:
When the key is inserted into a lock and turned clockwise, the lock switch moves to LOCK and grounds terminal 7 of the Central Locking Control Unit. The unit then activates the Lock Relay and applies voltage from the Fuse to the Lock Motor, which is grounded through the Central Locking Control Unit, terminal 2. The Lock Motor then pulls the Safety Catch Button. As the motor runs, a switch is moved from terminal 2 to terminal 6 of all the motors except the Driver's Lock Motor. At terminal 6, the switch position breaks the current flow from the Central Locking Unit Control Unit.

Unlock
When the key is turned counterclockwise, terminal 6 of the Central Locking Control Unit is grounded through the lock switch. The Central Locking Control Unit then activates the Unlock Relay and applies voltage from the Fuse through terminal 2 to the Lock Motor. The motor is grounded through the Central Locking Control Unit, terminal 1. The polarity is reversed and the motor pushes the Safety Catch Button lock up.
Image

What that tells us is that to get the doors on an e28 to lock & unlock with a keyless entry system, the system needs to mimic what happens when the key is turned in the lock. ETM tells us that turning the key to lock or unlock the doors applies a ground to a specific terminal on the Central Locking Control Unit. Above is screenshot from the ETM for the e28 showing the trunk lock motor, switch, and associated wiring & other components. As the diagram illustrates, the key switch center contact is connected to Pin 6 on the Trunk Lock Motor, which is connected to ground on the car. When the key is turned, that center contact connects with either Pin 3 (for lock) or Pin 4 (for unlock). Pin 3 has a Green/Black wire connected to it, and Pin 4 has a Yellow/Black wire connected to it, so getting the keyless system to work with this system is a matter of connecting it so that a momentary ground is applied to either of those wires.

Before starting the install, you need to decide where to put the remote unit. Most people who've made this modification chose the trunk (next to the trunk lock); that location has power and ground nearby, as well as the lock & unlock signal wires. It's also easy to access, far easier than inside the doors or next to the central control unit. That's the site I chose, and why I used the schematic that included that particular part of the car.

Next step is to determine how your system needs to be configured to work with the e28. Here is the wiring diagram from mine:

Image

It has ten wires on the connector; three for the lock signal, three for the unlock signal, one for power, one for ground, one for the tail lights (for flashing the lights and for visual confirmation when you lock/unlock the doors), and one for the trunk release. For my install, the last two were left untouched because all I wanted was the lock/unlock feature.

Image

The top-right schematic above shows that there are two SPDT (Single-Pole, Double-Throw) relays connected to the unlock and lock wires. A SPDT relay has a center contact (called Comm) and two other contacts, one that is normally closed (NC) and one that is normally open (NO). NC simply means that when the remote is doing nothing, there is a connection between that contact and COMM, and that connection is broken when you press the button for that function. NO means that there is no connection between that contact and COMM until you press the button for that function. The three wires in the connector associated with lock are attached to each of the three contacts in the relay; the first to the NC, the second to the COMM, and the third to the NO.

Now because the Control Unit in the e28 Central Locking System looks for a ground on one of two pins, what the remote system needs to do is connect one of the wires to ground momentarily; diagram C above matches the needs for the e28 best. For my installation I twisted the two COMM wires and the black ground wire together, and crimped a spade terminal onto all three wires. That spade terminal fit onto one of the screws that held a connector block to a metal bracket in the vicinity of the controller, and that worked well for a ground connection. Then I connected the Orange wire on the keyless unit's harness to the Green/Black wire in the car, and the Orange/Black wire on the harness to the Orange/Black wire in the car.

The system also needs power, but the nearest source of an always-on 12VDC in the trunk area is the trunk light. So I spliced a length of wire to the trunk light power lead near the left-side trunk hinge using an automotive wire splice. I ran that wire along the inside of the left rear fender, behind the felt inserts, then along under the taillights with the other wires, then used a crimp-on connector to connect it to the controller's harness. I plugged the harness into the controller, and it worked!

Well, mostly anyway.

The remote would lock the doors but wouldn't unlock them. After some testing I found that the wire splice I used on the Yellow/Black wire wasn't making connection somewhere. It turned out that the conductor in the wire on the remote system's harness was too thin for the splice to make contact with, so I ended up using a crimp connector instead. Others reported similar problems using the splice connectors, and suggested a better solution is to just avoid the splice connectors altogether. Using a crimp connector instead should work better; best solution is to strip the insulation and solder the wires together, then use insulating tape or shrink wrap to cover the bare wires.

After that, the only thing left to do is tidy up the wiring and put the rear trunk panel back in place. Done and done.

Clear as mud? Hopefully clearer than that. ;) Feel free to suggest edits to what's here or tell about your own adventures installing boopity boops.
Last edited by davintosh on Mar 10, 2018 6:52 PM, edited 2 times in total.
tn535i
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by tn535i »

I did almost the same thing I think you are describing above on my 6er all inside the trunk but I may have grabbed power from the antenna always hot wire. Here's a couple more ideas.

If you want to flash the turn signals instead of the park lights for example (brighter and more obvious)... you can't just apply power to one side with that purple wire, you have to do both L & R. That's what I wanted so I added a two pole relay after the 'purple' to flash but keep the left and right isolated. The purple is still the power but once relay open the L & R are isolated again. The park lights may work with single wire but I'm not sure and they are not that noticeable and the 6 has cool front turn signals.

The unit I purchased also had a status LED from the remote that blinks when the doors are locked and 'security' on. Since it was inside the trunck I simply slipped it inside one of the unused tail light lenses and you can see the little light blink inside the tail light cluster when the car is locked. You might call that a stealth like way to do it with no holes needed.

And if you do this in the trunk but double lock the drivers door I think it will then maybe unlock the trunk but nothing else.
Acid House
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by Acid House »

I have that same unit and it not only worked in my 528e for 3 years it moved to my 535i after the wreck and still works great 2 years later.

Best $20 or whatever mod. Had to replace fob batteries once.
vinceg101
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by vinceg101 »

Awesome Dave and timely too; I have been wanting to add this to the M535i now that we fully eradicatied the old Viper alarm and keyless remote locking system.
J.C. Whitney has discontinued selling the Valiant systems that several of us used in the past so I have been researching a replacement. There are tons of cheaper alternatives out there, so it shouldn't be a problem finding one.

Thanks for the write up, it is very informative and will use it moving forward.
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by cek »

Pretty happy with that same unit installed on Maytag. Wish this writeup existed when I did it because the other writeups were not as clear. Nice work sir.

The quality of the wires is crap (they are like 90% insulation and 10% wire, and the wire itself is like 72 gauge).

I find the little covers over the buttons useless and slightly annoying.

I'd go with something else next time for those two reasons.
davintosh
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by davintosh »

Thanks, Charlie. I'm with you on the wires; cannot believe how little conductor there is inside all that insulation. :roll: But I guess it's big enough to make it work. Just don't use the blue Quick Splice doodads; the slot in the contact knife will slide right by the conductor without touching it on either side.

Image

I usually just leave the cover on the remote open on mine, mostly because I forget to close it. When I first pulled them out of the package, I was bummed because the white part on one of them was scratched. I put that one on my keyring and gave the good one to my wife. Then one day I was fiddling with the thing and discovered that the white part was just a protective film over the chrome underneath. :facepalm: Doh.
e28Sean
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by e28Sean »

Davintosh,

That's awesome. We have the same boopityboops!
Image
ahab
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by ahab »

FYI - the "blue Quick Splice doodads" are called Scotch-Loks and the "boopityboops' are called fobs.

Only trying to educate the masses...

For those daunted by a full page of instructions it boils down to this. If you only want keyless lock/unlock it requires 4 wires (most likely, depending on the brand), can be done in the trunk behind the tail light panel, and takes under 15 minutes. Not intending to diss your efforts Dave, just hoping to get more people interested since it not only is a convenience, it's saves considerable wear and tear on some already fragile hardware. It's well worth the effort.
tn535i
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by tn535i »

Agree ^^^ The only mistake I made was not getting 3 or 4 of these to retrofit every BMW that has been in my driveway. I use my 5 more often than my 6 but only have put one on the 6 so far.
e28Sean
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by e28Sean »

ahab wrote:FYI - the "blue Quick Splice doodads" are called Scotch-Loks and the "boopityboops' are called fobs.

Sorry, no. They are actually called boopityboops. Very technical term, that. Ask Davintosh if you don't believe me.
davintosh
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by davintosh »

ahab wrote:FYI - the "blue Quick Splice doodads" are called Scotch-Loks and the "boopityboops' are called fobs.

Only trying to educate the masses...
Actually, if we're gonna get all technical & stuff, Scotch-Lock is a brand name used by 3M for quick splice solderless connectors (auf Deutsch, they're known as Schnellspleißlötdrahtverbinder, or at least that's what I think the guy at the autoteile store said.)

And I learned something new on that 3M page; there are multiple colors of the quick splice connectors, and the color indicates what wire size they are for. I've only used the blue, mostly because that's the only color I've ever found at auto parts shops. The blue is designed for 18-16 AWG; red is for 22-18 AWG, and yellow for 12-10 AWG, so the red might've been a better fit for this application. Of course, all sizes are readily available on Amazon; shoulda knowed that.

The boopityboops are, yeah, boopityboops. Fob works, but... There is some historical context to the term; somewhere around here is a thread where someone (I think it was e28sean) called them boopityboops, and I laughed out loud at that. My wife asked what was so funny, I told her, and they've been boopityboops ever since. I tried in vain to find that thread (bonus points for anyone who can dig it up!) My kids (adult kids) have picked up on the term too, so have the kids in our dorm now. I think it's only a matter of time before the term goes totally viral, and the whole world will be using it. ;)
ahab wrote:For those daunted by a full page of instructions it boils down to this. If you only want keyless lock/unlock it requires 4 wires (most likely, depending on the brand), can be done in the trunk behind the tail light panel, and takes under 15 minutes. Not intending to diss your efforts Dave, just hoping to get more people interested since it not only is a convenience, it's saves considerable wear and tear on some already fragile hardware. It's well worth the effort.
Yeah, it's a bit wordy, but I think it's sometimes better to have a little too much info than not enough. I'll likely edit the original post & use your paragraph as the start for a Reader's Digest, TLDR version to stick in at the top, keeping the firehose version below. Thanks!
e28Sean
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by e28Sean »

On a serious note, I think this is a fantastic write-up. Nicely done, dude.
Also, as for lights, out of sheer laziness, I wired the light-flash wire to the rear fog light on my install. I kinda like it, though.
davintosh wrote:The boopityboops are, yeah, boopityboops. Fob works, but... There is some historical context to the term; somewhere around here is a thread where someone (I think it was e28sean) called them boopityboops, and I laughed out loud at that. My wife asked what was so funny, I told her, and they've been boopityboops ever since. I tried in vain to find that thread (bonus points for anyone who can dig it up!) My kids (adult kids) have picked up on the term too, so have the kids in our dorm now. I think it's only a matter of time before the term goes totally viral, and the whole world will be using it. ;)
It was me, and it was in the "what did you do to your e28 today" thread. I had commented on changing the battery in the aformentioned boopityboops. Which, by the way, Davintosh, is a colossal pain in the rear-parts on the model you and I have selected. Wee tiny screws, and easy to misplace button parts.

Here's the context:
davintosh wrote:
e28Sean wrote:Replaced the batteries in both my boopityboops.

Image
Boopityboops. :laugh: That made me guffaw*; thanks for the laughs!
* then I had to explain to my wife & daughter what was so funny, and they got a laugh out of it too. boopityboops.
ElGuappo
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by ElGuappo »

Dave, love the write up, but agree you should start it with a TL;DR condensed version.
I too have used the fobs with the sliding cover, what a great upgrade for short money and ease of install.
mckend
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by mckend »

Is the central locking system negative or positively triggered ? If someone could answer I can solve my issues on remote install.
davintosh
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by davintosh »

mckend wrote:Is the central locking system negative or positively triggered ? If someone could answer I can solve my issues on remote install.
It’s negative. The missing images would show that, as will the ETM, which is a free download from http://wedophones.com/BMWManualsLead.htm

(I’m working on getting the images back. And kicking myself.)
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by cek »

mckend wrote:Is the central locking system negative or positively triggered ? If someone could answer I can solve my issues on remote install.
When are you going to fix your broken signature?
Karl Grau
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by Karl Grau »

This was my install for the Valiant 2RTA: http://www.mye28.com/viewtopic.php?f=3& ... 10#p302410
danix
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by danix »

Here's the 2020 update. I had installed an Avital system that was working great, it eventually worked only on lock, not unlock.
Replaced it with the same unit, still not working. Locking/unlocking with the key worked so I knew it wasn't the car.

I ordered and installed this unit: https://www.amazon.com/gp/product/B07QJ ... UTF8&psc=1
There are a few that are identical and from different brands. It's also very similar to the systems described here.
So a simplified howto:
  • order the unit from amazon
  • remove the rear inside trunk covering to expose the wiring harness
  • on the alarm harness, join the white, white/black and black wires, and connect these to ground
  • on the alarm harness, connect the red fused wire to 12v constant (I used the antenna lead)
  • connect the alarm orange wire to the car green/black (lock)
  • connect the alarm orange/black wire to the car yellow/black (unlock)
  • make sure everything works and tidy up
I ignored the other wires, not caring about flashing lights (the clunk of the locks is enough of an indicator!)
cek
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by cek »

The remote lock unit I put in Maytag ages ago failed right after I installed it. I had goofed with wiring it as well. Given these things are $19, I decided to just do it over. I bought this one this time:

Image
FICBOX Universal Car Door Lock Vehicle Keyless Entry System Auto Remote Central Kit with Control Box

The instructions suck. Use "Feature C" which is mis-lableled (it says it is positive trigger, but it is actually negative trigger which our cars need). Red goes to 12V. Black, yellow, and yellow/black go to ground. White/black goes to GR/BK (lock), and white goes to Y/BK (open).
Image

I should not have ordered this unit as it has trunk unlock. Instead, i should have gotten the same unit I got for Minerva which does not have the unneeded trunk unlock and is a whopping $4 less expensive.
12V Universal Car Remote Central Kit,KKmoon Door Lock Locking Vehicle Keyless Entry System, with 2 Remote Control

The good news is I can now tell the keys apart.
Image
danix
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by danix »

Funny, I was just cleaning the garage (in prep for selling my car) and I have pretty much the identical system available - for some reason I bought two, and this one is new and unused. $15 shipped and it's yours.
RonW
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by RonW »

cek wrote: Aug 27, 2020 12:09 PMI should not have ordered this unit as it has trunk unlock. Instead, i should have gotten the same unit I got for Minerva which does not have the unneeded trunk unlock and is a whopping $4 less expensive.
After I enabled the latent feature in the E28 that lets me use the power windows when any door is open even if the car is off, I took the unused wire from that feature's relay socket and wired it to the unused trunk signal on the Valiant 2RTA keyless entry I installed. Now when I hit the trunk button, the interior light turns on. Makes a handy car finder at night.
ianodoyle
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by ianodoyle »

Hey I’m locating mine under the kick panel and have wired into just below the central locking control unit. I would like to connect up the indicator lights. Anyone done this and know where to splice in? Somewhere at the back of the Hazard lights switch on the dash?

Thanks

Ian
e28Sean
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by e28Sean »

ianodoyle wrote: Sep 20, 2020 12:49 PM Hey I’m locating mine under the kick panel and have wired into just below the central locking control unit. I would like to connect up the indicator lights. Anyone done this and know where to splice in? Somewhere at the back of the Hazard lights switch on the dash?

Thanks

Ian

Ian, Hello. While I cannot provide any specific advice on where to splice in, most of these units (check yours to be sure) have two separate and isolated outputs for flashing lights. If yours does, the easiest would probably be to wire one output each to the left & right turn signal circuits.

As I had stated earlier, my boopityboop box is in the trunk, and I have my light blink output wired in to my rear fog.
sixseries
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by sixseries »

danix wrote: Feb 08, 2020 10:52 PM Here's the 2020 update. I had installed an Avital system that was working great, it eventually worked only on lock, not unlock.
Replaced it with the same unit, still not working. Locking/unlocking with the key worked so I knew it wasn't the car.

I ordered and installed this unit: https://www.amazon.com/gp/product/B07QJ ... UTF8&psc=1
There are a few that are identical and from different brands. It's also very similar to the systems described here.
So a simplified howto:
  • order the unit from amazon
  • remove the rear inside trunk covering to expose the wiring harness
  • on the alarm harness, join the white, white/black and black wires, and connect these to ground
  • on the alarm harness, connect the red fused wire to 12v constant (I used the antenna lead)
  • connect the alarm orange wire to the car green/black (lock)
  • connect the alarm orange/black wire to the car yellow/black (unlock)
  • make sure everything works and tidy up
I ignored the other wires, not caring about flashing lights (the clunk of the locks is enough of an indicator!)
I followed these steps, and for some reason, whenever I initially lock the car using the keyless entry fob, the car locks, and then unlocks immediately. I wait a couple seconds, press the lock button again, and the car locks and stays locked. Any idea why this would be the case?
e28Sean
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Re: Toward A More Comprehensive Keyless Entry DIY

Post by e28Sean »

Six, Does it do the same when you use the key in the door? Try from both the drivers door and the trunk. If so, your problem is on the car side of things. If not, check your wiring for the boopityboop box.
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