I have not done the job yet and am dreading it to be honest as I need to find that wire under the dash somewhere, I will be doing it shortly so will let you know if I find it.

What is an automatic dimmer?? What is a CDS cell?? What will the dimmer do and how will it work in simple terms as I am not an electrical engineer

 

it will, when turned on, put hi beams on and sense oncoming lights.
when oncoming lights are "seen" by the light sensor,cds cell, it will drop/dim the headlights.

that wire that pulls them up as you pull back on the lever should do it.
I looked by the module by the passenger kick panel but wasn't sure about it.

 

Thought that's what it was, but just needed it confirmed, will let you know when I finally do the job and find the correct wire.

 

Ok, wired the light switches up today as per GM Specification, and the strangest thing is that the roof lights work with the ignition turned off, but the grill lights only work with the ignition turned on.

Have only made connections temporary (twisting wires together and taping them up)

I have worked out which wire triggers the relay, and which one supplies the switch, I might try wiring the roof lights up to the same supply as the grill lights and see if they then both only work with the ignition on.

Then have to work out how to run them through the high beam circuit, so they get triggered by the high beam dipper switch.

Will grab some photos in the next few weeks of the lights operating once they are permanently wired and working as I want them to.

Then the next job will be fitting my Narva Long range driving lamps and wiring them up, two times pencil beam and one spread beam, and then install the winch.....never seems to end:

 

I though it was strange that the roof mounted lights would work that way also.... kinda an odd choice and not consistent with the way everything else works.

I would think that would work just fine.

I would think that the easiest place to do all this is in the fuse box. There is a hi beam relay in the fuse box and I would just piggy back off that relay right there - the grill and up top lights wiring is right there in the fuse box also obviously. Just add a relay to the high beam output circuit and feed the grill and top lights off the output side of the relay.

 

Never thought of that, brilliant idea, and should be able to do it without messing with any other wiring, just add a relay in the fuse box and run the power supply wire for the lights through it. It's so simple it could just work.

Thanks for that tip.

 

If you got creative with the piggyback connectors you could do it such that no wires are spliced into at all and the whole thing could be removed and put back to stock in a few seconds. You will need at least a DPST relay if you wanted to just control the hot side of the two light circuits. Not sure isolating the grounds is necessary, don't see why it would be needed, but I have learned that there are a lot of fairly sophisticated electrical things going on in the H3 and I tend to err on the side of caution whenever I make electrical modifications to mine. You might think about how many relays you are using and where - you have other lights to wire as I recall...needs a plan...

 

Yeah, the hummer electricals scare me a bit at times and I have rewired whole cars in the past, doing a custom wiring loom for another projects as we speak.

Will run a relay to the hot side only should be fine. Or considering leaving that alone and running a relay for the trigger from the dash switch. From the high beam dipper switch, so that if the high beams are on the relay will be activated letting power pass through from the dash switch.

Will update once I get a day off work again and I have a play.

 

I found the hi/lo beam wire going to the bcm. I finally pulled the c2 at bcm,connector to get at the wires since they use a number of purple wires. its pin one,purple in the corner,lower right looking at the conn unplugged.
I cleared some insulation and pulled it low ,ground with a 500 ohm resistor for safety and it worked so I can pursue the auto dimmer thing.

 

Cool thanks for that information, well I wired up both the roof and grill lights today and adjusted the lights in the garage, at this stage they are wired as per factory. So the grill lights get activated from the dash switch and only work with the ignition on, while the grill lights also activated from their dash switch work with both the ignition on and off

It appears that where the power is taken from the fuse box it is taken from a constant positive supply. Would love to know why GM decided to do it this way

Anyway will leave the lights as is for now and will rewire them at the fuse box end when I finally fit the brush guard mounted lights and harness.

Will grab some photos soon and post them up