Check Light with Headlight Conversion?

E28 technical advice asked and given! Troubleshooting, modifications and more.
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lswoboda
Posts: 84
Joined: Jun 12, 2018 5:22 PM
Location: Maryland

Check Light with Headlight Conversion?

Post by lswoboda »

Hello:

I have a 1988 535is with the original sealed beam headlights.

If I switch to an H4/H1 kit (not the euro set up) that is a plug-and-play solution, Will the check light be affected?

Said another way, if I switch from the original sealed beam, with the check light trip and stay on?

Obviously, I don’t want the check light to come on and I don’t necessarily want a hack to bypass it.

I was thinking of this set:

HTTPS://classicgarage.com/53hehekit.html

Thanks.

LS
Mike W.
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Joined: Feb 12, 2006 12:00 PM
Location: California Whine Country

Re: Check Light with Headlight Conversion?

Post by Mike W. »

No check light with H1/H4 headlights, I ran them for years. I forget exactly how it works, but I believe it comes on if there is not enough current being drawn, as the case can be with LEDs, not with a different amount or more current. As a matter of fact, I even ran 80-100 bulbs with no check light.

I should add that while it's been a while, I've ordered a number of times from Classic Garage and always been very happy. You can even call and spec custom bulb wattages at a minimal cost.
gadget73
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Location: New Jersey

Re: Check Light with Headlight Conversion?

Post by gadget73 »

should be a resistor wire, and it just measures voltage drop. Low current = low drop so the light comes on. At least thats how it works on every other setup I'm familiar with. So long as the lamp wattage is similar to what you're replacing it will be fine. If its higher it will still usually work, but possibly it won't trip the warning if one lamp goes out. Easy enough to test it by unplugging one.
lswoboda
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Joined: Jun 12, 2018 5:22 PM
Location: Maryland

Re: Check Light with Headlight Conversion?

Post by lswoboda »

Excellent! Thank you for the feedback.

I’m excited to get some new, better headlights without having any issues.

Thanks again.
gadget73
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Joined: Nov 22, 2017 10:30 PM
Location: New Jersey

Re: Check Light with Headlight Conversion?

Post by gadget73 »

know nothing specific about BMW electricals, but I got significant light improvements on my Lincolns with relay harnesses. There is a lot of voltage drop in the Ford setup, in the ballpark of 2 volts. That makes a big difference in light output, but it also breaks the lamp outage system. I figured the trade was worth it and pulled the lamp outage bulb. Might be worth doing a battery voltage vs voltage across the headlamps measurement to see how yours is doing.
Shawn D.
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Re: Check Light with Headlight Conversion?

Post by Shawn D. »

You won't have any issues with those headlights. They don't draw less than stock, which is what would cause the issue.

gadget73 wrote: Jan 27, 2022 2:23 PM should be a resistor wire, and it just measures voltage drop. Low current = low drop so the light comes on.
That's not correct. The system uses reed relays. Insufficient current, the relay doesn't close the check circuit.
lswoboda
Posts: 84
Joined: Jun 12, 2018 5:22 PM
Location: Maryland

Re: Check Light with Headlight Conversion?

Post by lswoboda »

Would a headlight relay setup be in order? If so, is there one that doesn't require destroying original parts and wiring?

Thanks!
Mike W.
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Joined: Feb 12, 2006 12:00 PM
Location: California Whine Country

Re: Check Light with Headlight Conversion?

Post by Mike W. »

They do draw more, I've seen various ratings on sealed beams but they generally seem to be in the 35W range compared to the 55-60 of the H1/H4s, but you're still only talking 5 amps. But I measured voltage on mine and I saw minimal drop, so I never bothered with a relay etc. But if you measure voltage and do find a drop, its easy enough to install. No need to disturb original wiring, all you would really need to do is add some, along with the relays. If it comes to that I can walk you thru it, but I'd measure voltages first before doing anything. Good clean connections are important though, and replacing the terminals on the wiring at the headlight might be in order too, they can get pretty crusty over the years.
lswoboda
Posts: 84
Joined: Jun 12, 2018 5:22 PM
Location: Maryland

Re: Check Light with Headlight Conversion?

Post by lswoboda »

A little off topic: Can I run Hellas with the city light holes even if I don’t use/install/wire the city lights?

I assume the lights would operate exactly like Hella non-city lights, but i want to make sure.

City lights might be a future project, but I plan to get new Hella lights to replace the sealed beams.

Thanks.
gadget73
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Re: Check Light with Headlight Conversion?

Post by gadget73 »

Shawn D. wrote: Jan 28, 2022 1:12 PM You won't have any issues with those headlights. They don't draw less than stock, which is what would cause the issue.

gadget73 wrote: Jan 27, 2022 2:23 PM should be a resistor wire, and it just measures voltage drop. Low current = low drop so the light comes on.
That's not correct. The system uses reed relays. Insufficient current, the relay doesn't close the check circuit.
fair 'nuff, functionally does the same thing though. Instead of the voltage drop switching on a transistor to turn on the lamp, it just does it electromechanically. Resistance is in the relay coil instead of in a wire.
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