Headlight problem: driving light switch activates high-beams!!
Thread Starter
Le Mans Master
Joined: Jul 2000
Posts: 7,635
Likes: 326
From: Greenville SC
Headlight problem: driving light switch activates high-beams!!
My friend and I put in E spec lights and used heavier gauge wire, relays, fuses, etc. We left the old wire intact, and only cut the wires at the connector that plugs into the light housing.
Why would the driving light switch also activate my high beams? We didn't even touch the driving lights! The driving lights stay ON when the high beams are on too! Yesterday I noticed that my headlights stayed on when down, the car was off, and the light switch was off! I had used the light and driving light switch to signal someone in the day time. I turned the key to ON, turned the lights on, and operated the driving lights a few times, then turned every thing off and the light went off as usual.
Any ideas?
Why would the driving light switch also activate my high beams? We didn't even touch the driving lights! The driving lights stay ON when the high beams are on too! Yesterday I noticed that my headlights stayed on when down, the car was off, and the light switch was off! I had used the light and driving light switch to signal someone in the day time. I turned the key to ON, turned the lights on, and operated the driving lights a few times, then turned every thing off and the light went off as usual.
Any ideas?
Thread Starter
Le Mans Master
Joined: Jul 2000
Posts: 7,635
Likes: 326
From: Greenville SC
Ran all new wires connected to the alternator.
Only place we cut wires was at the headlight connector, this shouldn't affect the other lights, but it does! When you turn on the highs the driving lights will go off when stock, but now they stay on.
Only place we cut wires was at the headlight connector, this shouldn't affect the other lights, but it does! When you turn on the highs the driving lights will go off when stock, but now they stay on.
Team Owner
Joined: Jan 2003
Posts: 20,304
Likes: 240
From: Summerland B.C. Canada
This is a cut and paste from the driving light upgrade info from tech tips.
NOTE: Research on the driving light subject indicates that some C4�s have their driving lights grounded directly to chassis ground. This setup is ideal for the above modification. Other C4�s have their driving lights grounded through the headlight high beam filament. What this does is that it will automatically shut the driving lights off when the high beams are turned on.
NOTE: Research on the driving light subject indicates that some C4�s have their driving lights grounded directly to chassis ground. This setup is ideal for the above modification. Other C4�s have their driving lights grounded through the headlight high beam filament. What this does is that it will automatically shut the driving lights off when the high beams are turned on.
Thread Starter
Le Mans Master
Joined: Jul 2000
Posts: 7,635
Likes: 326
From: Greenville SC
I'm confused, do I have the chassis grd, because both lights stay on, but it says this is ideal? If I have the other grd, why do both lights stay on? I think we are on the right track! We did ground to the fram, I think the same place it was origianally grounded, I remember cleaning the nut.
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Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
One clue is if the headlight is not at full brilliance then your driving light is using the 12v to the high beam filament for ground and a higher power driving light will cause the high beam to come on but not at full brilliance.
Thread Starter
Le Mans Master
Joined: Jul 2000
Posts: 7,635
Likes: 326
From: Greenville SC
I wouldn't be able to tell, the low's are brighter than standard highs, and the highs....fagetaboutit! I turned them on once and the car in front was to close so it went up in flames!
Le Mans Master
Joined: Apr 2002
Posts: 5,726
Likes: 46
From: Waukesha WI
St. Jude Donor '15
Check the wiring diagram in your shop manual.
In the case of my '90, the fog lamps are grounded thru the highbeam circuit. When I added my Hella 90/130s and rewired everything, I had to redo the grounds but I can't remember exactly what I did... it's been too long. Even after rewiring, my high beam indicator comes on when my fogs are on but the h-beams are off - fixing that was too much trouble.
Check your FSM to make sure you get it wired correctly - the circuit is not as simple as one would think. The '86 was easy to upgrade (same stuff as the 90) because it did not run the grounds the same way.
In the case of my '90, the fog lamps are grounded thru the highbeam circuit. When I added my Hella 90/130s and rewired everything, I had to redo the grounds but I can't remember exactly what I did... it's been too long. Even after rewiring, my high beam indicator comes on when my fogs are on but the h-beams are off - fixing that was too much trouble.
Check your FSM to make sure you get it wired correctly - the circuit is not as simple as one would think. The '86 was easy to upgrade (same stuff as the 90) because it did not run the grounds the same way.
Thread Starter
Le Mans Master
Joined: Jul 2000
Posts: 7,635
Likes: 326
From: Greenville SC
Well my friend and I spent hours on this, tried different grounds, read the FSM, etc. No luck. Now the fog lights don't come on at all!
My friend thinks it's the fog lamp relay, we couldn't find it! Where is it? It is supposed to be near the cruise control module. FSM says it is in the passernger side area under dash? We could access anything there, even removed the fuse panel!
My friend thinks it's the fog lamp relay, we couldn't find it! Where is it? It is supposed to be near the cruise control module. FSM says it is in the passernger side area under dash? We could access anything there, even removed the fuse panel!
