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It may, but I cannot guarantee that it will. See post #50 for my explanation why it might not. My solution is much cheaper and is guaranteed to work for 1990-up, although I cannot deny the allure of a plug and play solution.
50 watt load simulating resistors for both headlight bulbs.
So i imagine it wastes 100 watts, by turning the energy into heat, to make the stock electrical system think there are bulbs there.
Need a better solution before im on board.
I thought one of the whole 'points' of LEDs was the reduced power draw (and alternator load).
I think you may have misunderstood what my suggested mod does. What my mod does is draw a few millamperes extra current and a milliwatt or two extra beyond the LED consumption by using a 168 bulb to ground the foglight relay's coil and allow the headlights to work the way GM originally had designed.
I also do, however share your concern about throwing away heat and watts with resistors which may or may not work. See post #42 where I elaborated on this in great detail.
I think you may have misunderstood what my suggested mod does. What my mod does is draw a few millamperes extra current and a milliwatt or two extra beyond the LED consumption by using a 168 bulb to ground the foglight relay's coil and allow the headlights to work the way GM originally had designed.
I also do, however share your concern about throwing away heat and watts with resistors which may or may not work. See post #42 where I elaborated on this in great detail.
Ahhh. I stand corrected, i thought the 50 watt resistors from 'superbright led's ' was what you were proposing....
Ive had to do this a lot lately here it seems, but i shall bow out (but still follow) of this discussion 'tail between the legs'...
There was another solution to ground the foglights directly. Not sure how that turned out.
That would be me, thought I'd posted my results. It didn't work. The only thing I found that did work was Circuit Doctor's fix, relatively easy and works like a charm.
I modified my fog lamp relay circuit about 5 years ago to make my fogs operate normally when I converted from Halogens to HID's. You need to remove the knee bolster from the passenger side of the dash and locate the fog lamp relay (it should be the far right relay in the relay bracket). . Cut the lt grn wire from pin #5 (relay pin 86) about 2" from the relay base and add a 6" jumper of at least 18 Gauge wire with a ring terminal. Find a convenient screw and ground this new jumper wire to the frame of the dash. I used a small piece of heat-shrink tubing to insulate the end of the .5mm lt grn wire that comes from the dimmer switch.
Now, turn on your parking lights and test your fog lamps, they should light and your high beam indicator should be off (unless you have your high beams on).
Page 8A-100-1 shows the circuit in my 1990 FSM.
To undo this mod, just remove the jumper wire and re-connect the original lt grn wire to the relay pin #5.
Mick
Mick or anyone that have done this mod to your C4.
I noticed the cruise control stopped working after I did this mod. Did you have any problems with the cruise control after the ground was changed?
I have noticed it mentioned that the pre-90' cars are wired differently.
Anyone know if LED headlights will work in those cars without needing to re-wire or if not what has to be done to get everything working in a pre 90' car?
Why wouldn't somone installing these aftermarket lites just ground the fog lamp relay coil to wherever is easy ?? Is it really that important the fog lamps go out if the high beams are turned on ??? Seems like you coukd just turn the fog lights off via the switch.
and mine need this. what bulb did you go with? and did you use the relays? 
