Headlight issue....Need Help!

[SamHatco]

I'm trying to wire up the 69 firebird headlights to an 04 GTO wire harness and I've reached a roadblock. I'm used the 69 stuff but when you look at the 04 stuff it looks non capatible.

Here is a picture of the 04 GTO headlght connectors


Here is the 04 GTO schematics


Here is the 69 wire schematics


There are no grounds for the 04 connectors... so the question is how do I wire this up??? Any help is greatly appricated.

Sam

[CarlC]

Is the GTO a switched ground?

[SamHatco]

Is the GTO a switched ground?

I believe so, Carl.

Sam

[CarlC]

Verify if it is ground switched via a test light and volt meter.

If so, one option is to run auxillary sytems to power the body lighting. Since many of the body lights are chassis grounded it may be easiest to use the headlight switch to control a series of relays to control the headlights, running lights, etc.

Or, rewire the GTO switch to switch positive. This would be a cleaner install, if it is possible to do. Take lots of continuity readings to verify that there are no ground paths in the switch after the changeover. It would be pretty ugly to have a dead short in that part of the dash. This would only work if the switch controlled the lights directly. If the switch controls a relay, then it's is back to the above suggestion.

[BonzoHansen]

AM I reading that 04 gto diagram right, the headlights get constant hot and the relays are on the ground side?

Are you using the BCM and everything from the 04?

[SamHatco]

AM I reading that 04 gto diagram right, the headlights get constant hot and the relays are on the ground side?

Are you using the BCM and everything from the 04?

That is correct. I saw the same thing. The headlights get constant power from the tan and lt gn wires, however the wht/blk and wht/blu wires do not. I verified that with my test light.

I'm thinking of bringing the tan wire and the lt gn wire to one side of each light and the wht/blk wire to the other side of each light. Basically wire each head light separately and see what happens. I'll report later this morning.

Sam

[dhutton]

You can wire up the headlights directly to the bulb, just swap the postive to the common terminal of the bulbs and the switched grounds to the low beam and high beam terminals. The fog (parking) lights will be a different story since they have a grounded shell. You will need to use relays as Carl suggested. The side markers are not grounded so you can used them directly as they are.

[SamHatco]

got them working! Here is what I did. Like I said previously I wired the high beam wire to one side of the high beam light and one of the wht/blk wires to the other side of the light. I then wired the low beam wire to the center prong of the low beam light and used the other wht/blk wire to the high beam prong of the low beam light (does that make sense?). So basically both lights are wires separately. Crossed my fingers (thats the important part) and turn on the switch. BINGO! lights. Like Carl picked up on the switch controls the ground to complete the circuit. Even though I have constant power to the lights, without the ground switched on nothing happens. I read somewhere that the new cars rely on switched negatives on relays, instead of switched positives on switches like the old days. Supposed to safer and more efficient. Anyway it works, my low beams are brighter since they are always on high and the high beams appear to brighter also.

Whew, glad that worked out. I was worried I was going to have to reinvent the wheel, so to speak, to make them work.

Sam