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fog lamps quit working help please

tboz1

Full Member
Joined
Feb 13, 2011
Messages
22
my fog lamps stopped working also the door switch lights dont work ive looked at the switch seams fine
the cargo lamp part works but when i press the fog lamp switch it dosent light up or work ive replaced the relay checked all the fueses in the side of the fues panel in the dash on the left side also under the hood took apart the relay triped it manualy the fog lights work fine so seams like its not getting a signal to trip the relay?? any ideas? I took the main fues panel apart as much as i can think it had 4 main plugs in it maybe more i was going to run the relay manualy but i cant tell what wire trips the relay?? and idk if the main fues box will comapart anymore to better locate it any ideas? anybody have a wiring diagram its a 2002 ext thank you for your help
 
you might want to check ALL the fuses, the BCM1 in particular I think it is, can't remember for sure.


Didit
 
lookf or the thread ab out full time DRLS. I believe that has instructions on taking it apart
 
headlights on...
fog light button pressed does a little light light up near fog light switch to indicate it is on?

If yes go look at fogs..
check bulb, bulb socket & wiring.

If not have switch checked..

If memory works... switch tells BCM to turn on fogs...
 
ok went to auto zone got a online cd checked it out heres what i have so far
A=black=ground B=purple=Front Fog Lamp Supply Voltage C=Orange=Front Fog Lamp Switch Signal D=gray=Instrument Panel Lamp Supply Voltage E=dark blue with white stripe=Cargo Lamp Low Control
so A i should have no voltage lol because of ground easy one
B the purple wire front fog lamp supply so im just guesing I should have 12.5 volts +or-
C the orange wire is switch signal ? so should it have  voltage on it also?
D the gray wire insturment panel light im just guessing this is almost like a acc wire just on when the light are on?
and E the blu with wht wire speaks for its self

lol ok now heres the big question can anybody tell me what wires to jump to get the relay to trip a signal to turn on  ???  also is there a way to test the switch seams to work fine to me i took it apart and really not that much going on in there  heres some diagrams iI got off this dvd
 

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C should have power when switched on is my guess
 
ygmn said:
C should have power when switched on is my guess
I'm thinking C is 12v+ when the truck is running and when the button is pushed, B (purple) becomes hot.
I can't make out the schematic to be sure though.
 
i tried to upload a bigger pic but it wont let me you can try to hold ctrl and the plus key that will change the screen size to what ever you want to  (y)  thank you for the help
 
Does this help anyone, and can you hear the relay click when you turn the fogs on.


Fog Lamps
With both the ignition switch in the [RUN] position, and the park lamps ON, the fog lights will illuminate when the driver places the fog lamp switch in the ON position. The FOG LPS 15 A fuse in the engine wiring harness junction block supplies battery positive voltage to the fog lamp relay switch circuit. The park lamp relay supplies battery positive voltage to the fog lamp relay coil. With the headlamp switch in either the park or headlamp position, and the fog lamp switch is paced in the ON position, the body control module (BCM) will energize the fog lamp relay control circuit. The BCM receives the park lamp ON signal from the interior park lamps supply voltage signal circuit. The current flow is from the fog lamp relay to both front fog lamps and to ground G100. The state of the fog lamps will remain the same until the fog lamp switch position is changed, or the ignition switch is cycled OFF and ON. Fog lamp operation will be cancelled whenever the park lamps, are turned OFF or the high beam headlights have been selected.

The rear fog lamps are controlled in much the same way, however the front fog lamps must be on in order to turn on the rear fog lamps. The rear fog lamps have there own relay, and both the relay control and current flow are the same as the front fog lamps.

 
tboz1 said:
i tried to upload a bigger pic but it wont let me you can try to hold ctrl and the plus key that will change the screen size to what ever you want to  (y)  thank you for the help
Orange is the supply to the switch to close it. Purple out of the switch is hot when the switch is activated. Check the purple with the switch pushed and see what you have. The orange is coming from the BCM let's the switch activate (i.e. truck is running)


Thanks for the tip on making the pix bigger. (y)
 
ok the relay dosent click the switch dose not light up it only lights up when i trip it manualy by taking the relay apart here are some more diagrams might come in handy  (y)
 

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its called all data    not really that good though but it deff helps
 
tboz1 said:
np    can you figure out anything with those pics
Pull the switch out so you can get to the plug on the back while it's still connected. Start the truck, turn the headlights on (although it shouldn't matter) and take readings on the orange and purple wires. push the botton to turn the fogs on and do it again. If you have voltage on the orange and not the purple AFTER you push the button, the switch is bad. You may have to poke into the wires to get the readings.
 
ohiobellboy said:
I'm thinking C is 12v+ when the truck is running and when the button is pushed, B (purple) becomes hot.
I can't make out the schematic to be sure though.
my bad I ee schematic now I was guessing based on description
 
Well looking at schematic...

you need power in on wire C from BCM
Power out when switched on on wire B turns on LED this only comes on when RELAY switches on.

A has to be to ground so check for continuity.

Check C2 from BCM to Fog Relay for power when switched on.
CHeck for power into fog relay. (Fuse)

If above is good then check relay
 
another question. Have you checked them with the truck running or at least the key turned to the ON position? They don't work without either of those two being done.
 
havent had time to mess with it yet  :E:  been swamped with work ill look at it tomorrow though and let yeah know (y)
 
This may be overly simplistic but on my truck the actual fog light switch was pushed into the dash module slightly sideways and did not actually push in properly. Once I pulled out the module and reseated the switches my lights worked just fine.
 
Sorry but I have to ressurect this old post.
I don't know if this issue was ever resolved but I have this exact same problem on my 02 Avalanche.
What I should add is the initial post states that the door switches no longer illuminate as well. That is exactly what is happening to me.
In addition to the fact that the fog lights are not coming on, all 4 doors switches( power windows, door unlock and lock etc) have lost the capability to illuminate when the lights are turned on.
My dash and radio still illuminates but not the doors. So while all the past posts have focused on the fog lights I don't think the problem is from there specifically. I am leaning towards something with the parking lights system
I also noticed that my parking lights no longer blink when I press the lock or unlock on my key fob for the alarm. They do however come on at night when the headlights are on.
I also have aftermarket lights on my bull bar connected to to a separate relay which gets power from my parking lights so they only come on with the parking lights on and those are also not turning on when driving. Strangely though if I leave the switch on for those lights on my dash and press the button on the remote, they blink even though the parking lamps don't. I am almost certain it is a fuse somewhere since that light gets power directly from the battery but uses the switched source from the parking lights circuit to drive the relay.

Any help would be deeply appreciated.
Thanks


 
Just noticed my chimes don't work if I leave the lights on and open the door to get out of the truck with the ignition off as well
 
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