myraus

Hi,

I know this is done to death on here, but the threads I've found didn't seem to explain what I want well enough. Here goes...
I built a headlight harness upgrade on my 91 but, being a Canadian XJ, I'd like to keep the functionality of my DRL intact. Not just for operational purposes but also for legality.
Has anyone found a way to make both systems work together?

ijeeep

Following with interest.

boxburn

Reading the FSM description of how the DRL's work, I can't see what issue would be caused by running a relay harness. From what I gather, when the key is in RUN, the DRL module provides power to the headlamp circuit which should then trigger the harness relay and turn the headlights on.

Edit: Or do they run at a lower voltage/brightness? If so that sounds like a similar issue I had with I believe my dimming module which I removed the fuse for due to it buzzing my relays. Not a legal requirement here, at least it wasn't back in 95. I'm going to have a think about it as it was a feature I quite liked.

moonsandals

Also Canadian. I unplugged the DRL module and haven't gotten around to actually fixing this since last summer. So take what I say with a grain of salt.

The DRL module sends a low voltage signal to the headlight. This causes the lights to be dim when DRLs are on - that's the design. The low voltage causes the relays the flicker and they will not work properly and will fail.

The solution I have found is to basically splice the DRL module wire in on the headlight side of the harness and not in the relay side. I'd have to double check wiring schematics to be certain, but that won't happen any time soon so don't wait for me to look it up. From memory you cut the wire from the DRL module (the one on the harness that goes to the relays) and run a new wire spliced in to connect to the headlight side of the relay so it now powers the headlight instead of the relay.

I had other ideas as well, but mostly more complicated and would be more of an "upgrade". When you realize how the DRL module works you can use that in different ways, or use voltage regulators to change the voltage back to 12V to get relays to work again (or wire the DRL signal to other lights).