adding a factory fog light wiring harness?

[Guest TurboSedan]

i have a headlight wiring harness from a '91 DOHC Cutlass Supreme and was wondering how easy/hard it would be to swap it out?

 

it's the entire underhood headlight/foglight/parking light/turn signal harness. i think it's the same as what i have now except the current one in the car has no wiring for fog lights. this one also has a forward lamp relay center whereas my car has nothing like that right now.

 

some questions:

 

- where is the firewall plug? it's been so long since i've pulled it out of the donor car i can't remember i hope it's not too hard to access. i looked around on my car but didn't see it. if my car doesn't already have a hole in the firewall for this harness i'll probably just sell it instead.

 

- where does the relay center mount? driver's side of engine bay somewhere?

 

- i also have the matching underdash harness that comes from the firewall plug. it's about 15" long and i have no idea where it plugs into under the dash?

 

- is there anything else i need? i already have the instrument cluster bezel with the fog light switch in the car and i also installed the BYP bumper. my car already had the wiring for the switch even though my car didn't come with fog lights from the factory. i'm not sure where the wires from that switch go to though.

 

any help appreciated, thanks

[LukeZ34]

I know the relay center mounts behind the cover on the passenger side (by the ECM)

But that's all I know on the topic..

[ns87]

The Foward Electrical Relay center which has fog light relay also has the horn relay. You can keep your old horn relay too I guess. Re-wiring is easy, except the horn uses two different orange wires for some reason If you're not in a hurry, next week I can go to my car and figure out which orange wire goes where. If you mess up, I think the horn will always stay on until you hit the horn pad.

 

I got mine from a 89 CS, so maybe it changed since

[ToroToro]

The fog light wires go through the same hole as the headlight wires... to the right of the brake booster and little ways down. It's a PITA to reach.

 

As far as where the wires end up...I'm thinking there is just empty pins at the electrical center plug...so if you were to plug in the foglight electrical center, they would work fine. This is true for the '94 at least.

[Guest TurboSedan]

cool, so far it sounds like it might be as easy as plug n play. i'll have to take a look and see if i can get to that plug without removing the brake booster.

 

and yeah, this new harness i have also has 2 plugs for the horns although both plugs are green/black wires not orange. i might just leave them unplugged; i'll have to see how the current wiring for the horns is.

 

thanks![br]Posted on: April 28, 2006, 10:35:39 AM_________________________________________________wow, this is a bitch. i just got the original wiring harness completely out of the car. i had to remove the alternator, rock the engine forward, partially remove the heater core pipe and get it out of the way, take the plastic cover partially off the firewall, and then put car on jackstands and remove the passenger side wheel just to access the plug! ugh. on the bright side it was easy to access the short 15" harness under the dash. i also had to remove the battery to unplug the horns and the side marker and turn signal lights. removing the wiring from the header panel was pretty tedious but i managed to do it without breaking or cutting anything.

 

now to get this other harness installed. it looks like it will be almost 100% compatible except the turn signal lights on the front side of the bumper are different. my old harness has 3 wires going to a socket whereas this new one just has 2 wires going to a weatherpack connector.[br]Posted on: April 28, 2006, 01:46:17 PM_________________________________________________ok i got it done and everything went fine except that i now have no front turn signals. why is the wiring for the front turn signals different between the coupes and sedans? i figured the turn signal was simply in a different location and that was it. the original wiring harness had 3 wires going to the front turn signal bulb socket. the coupe wiring harness i just put in has two wires going to a weatherpack connector for the turn signals. anyone know what i need to do to get the front turn signals working again?

 

my rear turn signals and everything else works for that matter. the fog light switch by the cluster now has a use! i don't actually have fog lights in the BYP bumper (yet) but i did check the function of the switch with a voltmeter to varify it.

 

btw if anyone has foglights & brackets for the Cutlass BYP bumper PM me

[Bossman429]

Alldata is not showing any difference between a coupe and sedan on the front turn signal wiring diagram.

 

Typically a 3 wire bulb socket is for cars with a turn/parking light. That is, it uses a dual element bulb, has one element on with parking lights, and the other comes on to indicate a turn signal. This would be just like a brake/turn signal bulb in the back.

 

Alldata is showing the brown wire to be the positive for the parking lights.

The light blue wire is the positive for the turn signals.

And of course black is the ground.

 

Since you no longer have 3 wires, you may have to rig something up, I guess. I have looked in Alldata under 90, 91, and 93 Cutlasses, and they all have the 3 wire setup.

 

You might want to get your hands on a wiring diagram if you haven't already.

[Guest TurboSedan]

i found that i actually have two problems. no front turn signals and no front parking lights. i don't have wiring diagrams handy but i looked around and i think i know how to fix each problem.

 

turn signals. i am going to chop off the 2-wire weatherpack connector for the front turn signals and splice on the 3-wire bulb socket from the old harness. i checked the 2-wire connector with a voltmeter and it does have on/off 12 volts when the turn signals are on. the 2-wire connector has a blue and a black wire; which i can just splice right onto the blue and black wires on the 3-wire bulb socket. the 3-wire bulb socket also has a brown wire, which i'll just splice from the brown wire used for the corner/parking lights. that should give me turn signals and parking lights for the front bumper.

 

corner/parking lights. the new harness i have is a bit different from the old harness for corner/parking lights. it still uses a brown wire for power (verified with voltmeter), but the driver's side uses a yellow wire and passenger side uses a green wire for ground. i have no idea why GM did it differenly for the coupe and sedan harnesses. unfortunately, neither the green or yellow wires are grounded. i traced the green and yellow wires back to the underdash plug and sure enough, there is no ground source for them there. the dash side of the plug simply has empty slots where the green and yellow wires go. i was planning on supplying an underdash ground to these empty slots for the yellow and green wires, which should give me working corner/parking lights.

 

everything else works great - hi & low beams, horn, and foglights are all working like they should. the wierd thing is that the new harness i put in from the coupe has 2 wires i have no idea what are used for - a big white wire and a big pink wire. there is nothing going to these wires from the underdash plug, but everything seems to be working fine. i'll have to check a wiring diagram to see what these are for. [br]Posted on: April 28, 2006, 10:53:19 PM_________________________________________________well i spliced the 3-wire bulb socket over to the new harness and i now have front turn signals at the front of the bumper so that's good. the only problem now is the front corner/parking lights.

 

can anyone tell me if the front corner/parking lights work as turn signals? or are they parking lights only? if they are just parking lights then it will be an easy fix but if they flash i'm not sure what i'll do to get them working properly.

 

i wish i had a FSM for a '91 Cutlass the FSM supplement for my STE is way different and the wiring diagrams in the Mitchell manual and AllData don't seem to be correct. if someone has a '91 Cutlass FSM if they could scan and post (or email me) the C150 connector (pin & socket side) that would be GREAT!

[ns87]

can anyone tell me if the front corner/parking lights work as turn signals? or are they parking lights only? if they are just parking lights then it will be an easy fix but if they flash i'm not sure what i'll do to get them working properly.

 

They are turn signals

[Guest TurboSedan]

thanks. that means the yellow & green wires for the parking/corner/turn signals isn't simply a ground. i'll just have to get an FSM to figure it out.