Fog lights not working, '95 coupe
05-10-2012, 02:00 AM
#1
Intermediate
Thread Starter
Fog lights not working, '95 coupe
When I bought my car four and a half years ago the fog lights worked, but I never used them since only one side was working. Several years ago I had an accident which did mainly minor cosmetic damage but when it was in the shop I bought an exterior bulb kit to replace all the exterior bulbs figuring it'd be easier since they'd have the bumpers off anyway. I don't know if they actually replaced them all or not but as long as I've tried using them they haven't worked. I checked the fuses, at least the couple that I suspected could be the right one but none blown. I checked the wiring that I can actually see or get to and no obvious problems there. I checked the bulbs and the filaments look ok but being halogen I didn't know if they blow like a typical bulb where the filament is obviously broken or if they just sort of stop working with no obvious visible signs that they don't work. I don't want to just go out and buy new bulbs if that isn't the problem so I figured I'd ask on here and see if anyone has any suggestions. I have a volt meter I can use to check power at the sockets but I'll need some guidance as I don't know where exactly to stick which prong.
05-10-2012, 11:18 AM
#2
Melting Slicks
Member Since: Nov 2005
Location: Green Valley Arizona
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The probes on your voltmeter are probably too large to fit into the bulb sockets, so just get two small wires...stick these into the sockets and with the driving/fog lamps switched to ON....measure the voltage across the two sockets...it should be 12 volts.
Check both sides. If not 12 volts, then have to check the switch...assuming the fuse is good.
Check both sides. If not 12 volts, then have to check the switch...assuming the fuse is good.
05-11-2012, 12:42 PM
#3
Melting Slicks
Member Since: Aug 1999
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The Fog lights requires 12 volts from Tail Fuse #6 15amp fuse
which is hot at all times.
Turn the Headlight switch to Head or Park.
Turn the Fog Lamp switch On, does the
LED indicator for the Fog switch light?
If it does, the Headlight and Fog lamp switch, and
fuse are good.
Turn the Headlights On.
Then turn the High Beams On.
Do both High beams work?
If they don't the High beam filaments are probably
blown or 12 volts is not getting to them.
The Headlight bulb socket has 3 wires going to them.
Black is Ground.
Disconnect the plug at one of the headlight bulbs.
With the Headlights on and High beam switch on
verify you have 12 volts with one meter probe on the Black
wire the other meter probe on the Light Green wire at the plug
socket.
Light Green is 12 volts for High beam.
Tan is 12 volts for Low beam.
With headlight Low beams on and Fog lamps on, verify you have 12 volts at either of the Fog lamp bulb sockets.
Black wire is grouind, Purple wire should be 12 volts. If you have
12 volts, either the bulb socket is bad or the bulb is blown.
If no 12 volts, the Fog relay could be bad.
The Fog light relay is located along the front edge bottom of the passenger side
of the Dash. there are 5 relays plugged into sockets.
There are 6 socket holders. One is empty. The Relays are
Blank/unused socket
Courtesy lamp relay
Fog lamp relay
Fuel pump 2 relay (used for ZR1 LT5 may or may not have a relay installed).
Fuel pump 1 relay
Horn relay.
The relays are all the same so they can be swapped around.
Also Note: The Fog lamps will not work if the High beams are on.
which is hot at all times.
Turn the Headlight switch to Head or Park.
Turn the Fog Lamp switch On, does the
LED indicator for the Fog switch light?
If it does, the Headlight and Fog lamp switch, and
fuse are good.
Turn the Headlights On.
Then turn the High Beams On.
Do both High beams work?
If they don't the High beam filaments are probably
blown or 12 volts is not getting to them.
The Headlight bulb socket has 3 wires going to them.
Black is Ground.
Disconnect the plug at one of the headlight bulbs.
With the Headlights on and High beam switch on
verify you have 12 volts with one meter probe on the Black
wire the other meter probe on the Light Green wire at the plug
socket.
Light Green is 12 volts for High beam.
Tan is 12 volts for Low beam.
With headlight Low beams on and Fog lamps on, verify you have 12 volts at either of the Fog lamp bulb sockets.
Black wire is grouind, Purple wire should be 12 volts. If you have
12 volts, either the bulb socket is bad or the bulb is blown.
If no 12 volts, the Fog relay could be bad.
The Fog light relay is located along the front edge bottom of the passenger side
of the Dash. there are 5 relays plugged into sockets.
There are 6 socket holders. One is empty. The Relays are
Blank/unused socket
Courtesy lamp relay
Fog lamp relay
Fuel pump 2 relay (used for ZR1 LT5 may or may not have a relay installed).
Fuel pump 1 relay
Horn relay.
The relays are all the same so they can be swapped around.
Also Note: The Fog lamps will not work if the High beams are on.
Last edited by Hooked on Vettes; 05-11-2012 at 01:13 PM.
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1993C4LT1 (12-02-2023)
09-20-2017, 01:32 PM
#4
I try to continue on this thread despite it has not been updated for years, because this has been useful for me so far, and I have the same issue on my 90 ZR1.
Basically, some time ago the fog lights worked, then they stopped, both.
I have removed the bulbs, and one was blown, thus I have ordered 2 new bulbs - once I installed them, still no light, from both of them.
I have checked the relay, and it is OK.
The switch shows the green led when ON, thus, according to this thread, both switch and fuse are good (I checked the fuse anyway, and I confirm it is OK).
The problem is, that when I switch headlights on, and fog lights on, instead of getting 12V to the 2 bulb sockets, I get 0.33 on the left side, and 0.14 on the right. When I switch either fog lights, or headlights off, I measure 0V (as expected).
Do you have any advice on what to check next? I hope not the cables, as it would be very difficult...
Thanks in advance!
Basically, some time ago the fog lights worked, then they stopped, both.
I have removed the bulbs, and one was blown, thus I have ordered 2 new bulbs - once I installed them, still no light, from both of them.
I have checked the relay, and it is OK.
The switch shows the green led when ON, thus, according to this thread, both switch and fuse are good (I checked the fuse anyway, and I confirm it is OK).
The problem is, that when I switch headlights on, and fog lights on, instead of getting 12V to the 2 bulb sockets, I get 0.33 on the left side, and 0.14 on the right. When I switch either fog lights, or headlights off, I measure 0V (as expected).
Do you have any advice on what to check next? I hope not the cables, as it would be very difficult...
Thanks in advance!
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L98-C4-HI (12-21-2017)
12-19-2017, 02:05 PM
#7
Advanced
Hopefully can revive this thread for help. New owner of a 1994 Convertible and thought the fog lights worked when I first purchased it, now both do not work. Have replaced both bulbs and replaced fuse #6 although it was not bad when removed. Seem to have power at bulbs and light does come on above switch. I read this about a relay located under passenger side dash. For the life of me I can't see any screws there to remove that panel. And also can't find any part number associated with a fog light relay to replace. Any pictures and guidance would be greatly appreciated. This poor car has been sitting neglected in the Arizona sun with top down for two plus years but excited to restoring my first vette back to life. .
12-20-2017, 01:40 AM
#8
Le Mans Master
Member Since: Oct 2004
Location: Everett WA
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C4 of Year Finalist (appearance mods) 2019
Congratulations and welcome to the world of C4
I don't have an answer to your specific question but I'm sure that several people do and will chime in.
If you're going to be working on the car yourself be sure to purchase the red two volume Factory Service Manual for your particular year. They are full of diagnostic info and its great for helping in the proper order of disassembly and reassembly.
I don't have an answer to your specific question but I'm sure that several people do and will chime in.
If you're going to be working on the car yourself be sure to purchase the red two volume Factory Service Manual for your particular year. They are full of diagnostic info and its great for helping in the proper order of disassembly and reassembly.
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RWC4PHX (12-22-2017)
12-21-2017, 05:49 AM
#10
Hopefully can revive this thread for help. New owner of a 1994 Convertible and thought the fog lights worked when I first purchased it, now both do not work. Have replaced both bulbs and replaced fuse #6 although it was not bad when removed. Seem to have power at bulbs and light does come on above switch. I read this about a relay located under passenger side dash. For the life of me I can't see any screws there to remove that panel. And also can't find any part number associated with a fog light relay to replace. Any pictures and guidance would be greatly appreciated. This poor car has been sitting neglected in the Arizona sun with top down for two plus years but excited to restoring my first vette back to life. .
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RWC4PHX (12-22-2017)
12-22-2017, 04:20 PM
#12
Racer
fog lights
i have the same problem, i installed led headlights,,,which are great, but i have no fogs and when i push the fogs high beams turn on no voltage to the fog plugs.
06-15-2018, 04:47 PM
#14
The Fog light relay is located along the front edge bottom of the passenger side
of the Dash. there are 5 relays plugged into sockets.
There are 6 socket holders. One is empty. The Relays are
Blank/unused socket
Courtesy lamp relay
Fog lamp relay
Fuel pump 2 relay (used for ZR1 LT5 may or may not have a relay installed).
Fuel pump 1 relay
Horn relay.
So this is what I see under the airbag. Could you please give me a hint where I can find the fog lights relay?
Many thanks in advance!