I searched but couldn't find an answer. I have aftermarket harness/switch with oem foglights. I am currently using an aftermarket switch to turn them off/on. I would like to know if there is a way to use an oem switch with foglight button to turn off and on. I can splice the aftermarket harness, just want the oem look!! Any ideas/suggestions??
Fog light question
- Thread starter dvibbert
- Start date
This has come up a couple of times, but not often. Since the fog lights are controlled by the BCM, the only way to make them work with the OEM switch would be to tie the output of the fog light indicator LED to trigger a relay that feeds the fog lights. This is provided the fog light enabled switch would still function the same and the LED isn't fed by the BCM response. Research in the wiring diagrams would be necessary.
If you knew of any other members in your area that had an OEM switch, you could have a mini meet, swap their switch into yours and see if the fog light indicator light comes on when you hit the button. Then you'd know for sure, and if it worked, then it would be easy to wire something up to it.
I am afraid that power and ground for the fog light LED both come from the BCU.Blckshdw said:
If your electronically inclined, make a latching relay circuit with four relays. Use the factory switch to supply the ground pulse.dvibbert said:
If you are even more electronically inclined and want to use less space then us an IC chip, resistors, capacitors, and diodes on a circuit board. Read here. http://forums.bit-tech.net/showthread.php?t=211978
Three hours away. Im not up for the drive but he is then, im sure it is not much too remove the head light switch. Dunno if the envoy headlight washers will make any difference in the harness connector though. There are a couple of members closer to ya on the member map. Send them a message.Blckshdw said:
Ok. Last question because I have researched and understand the wiring. I have the fuse and relay, as well as the correct headlight switch. The orange wire is in the 8 pin harness. I understand that the foglight works from the BCU. Is it possible to just swap out the BCU from a TB that had the foglights? Thoughts??
I've swapped BCMs between 2 vehicles on our platform before, you just have to do the security relearn procedure (key on, but not started for about 20-30 minutes until the security light stops flashing). As long as the new (to you) BCM has all of the same other features programmed that you have, it should work.
AtlWrk
Member
- Joined
- Dec 6, 2011
- Posts
- 674
Would you be able to find a same-year BCM where the only difference in options is the fog lights?
To answer your question a few posts back about swapping the switch: YES.
How good are you with soldering? Do you still have your old headlight switch?
1) Open the old switch housing and unsolder and remove the dome light override (it's a push-on/push-off style) switch inside the old headlight. Use it to replace the momentary-style fog light switch in the new headlight switch. Tip: pay close attention to how the headlight switch comes apart, it can be a little tricky to get everything in position to put back together correctly.
2) Connect the Orange and Dark Green/White stripe wires at the 8-wire headlight switch connector (short/jump them together).
Your fog light button now grounds the dark green/white stripe wire with an on/off switch (no latching relays, elaborate circuits etc., needed) AND it also activates the fog light indicator LED
Now you can use the dark green/white wire to control the relay in your harness AND have the indicator, OEM style.
It also activates the fog light relay in the underhood fuse box
BUT note that it's not on an ignition-switched circuit so you'll drain your battery if you forget to manually turn them off, or wire another relay between the switch and relay to cut the power when the ignition is off. (I have a relay wired to the parking light circuit for this). I went so far as to tear into the front fuse box and added the terminal/wire for the fog lights (the only part of the system not already present in the truck) so no aftermarket harness needed. 
If you're already passed this point, grounding the dark green/white stripe wire turns on the LED indicator. You could work that into whatever setup you ended up with.
To answer your question a few posts back about swapping the switch: YES.
How good are you with soldering? Do you still have your old headlight switch?
1) Open the old switch housing and unsolder and remove the dome light override (it's a push-on/push-off style) switch inside the old headlight. Use it to replace the momentary-style fog light switch in the new headlight switch. Tip: pay close attention to how the headlight switch comes apart, it can be a little tricky to get everything in position to put back together correctly.
2) Connect the Orange and Dark Green/White stripe wires at the 8-wire headlight switch connector (short/jump them together).
Your fog light button now grounds the dark green/white stripe wire with an on/off switch (no latching relays, elaborate circuits etc., needed) AND it also activates the fog light indicator LED
Now you can use the dark green/white wire to control the relay in your harness AND have the indicator, OEM style.It also activates the fog light relay in the underhood fuse box
BUT note that it's not on an ignition-switched circuit so you'll drain your battery if you forget to manually turn them off, or wire another relay between the switch and relay to cut the power when the ignition is off. (I have a relay wired to the parking light circuit for this). I went so far as to tear into the front fuse box and added the terminal/wire for the fog lights (the only part of the system not already present in the truck) so no aftermarket harness needed. If you're already passed this point, grounding the dark green/white stripe wire turns on the LED indicator. You could work that into whatever setup you ended up with.
We were able to put my BCM into an 03 Voy, and it was driveable once the relearn process finished.AtlWrk said:
My fog lights stopped working. The indicator light doesn't illuminate either. I checked the fuse (good) and tried a new relay since I don't know how to test them. So I suspect it's the switch itself or wiring somewhere along the line. I have 2 questions: How do you remove the switch panel, and (I feel dumb) can a relay be inserted either way, ie rotated 180 degrees?
You can remove the switches from the side of the dash. With the driver's door open, you'll see a panel on the side of the dash that's usually covered by the door. Use a trim removal tool (or butter knife) to wedge it in and pry the panel off. It's held in by 2 plastic pins.
From there reach inside and feel for the back of the switch box. There are 4 plastic clips, 2 on each side. Squeeze them in to release them. Push on the switches from the front, and it will release into the open section where your hand/arm is. Then you can pull it out the side, and release the 2 wiring harnesses on the back.
I would assume the relays should go in 1 way, but generally those have a pin configuration so you can't plug them in incorrectly. It really comes down to where the pin assignments are. If it's a 4 pin relay, and the coils contacts are diagonal from each other, then it wouldn't matter how you inserted it. But if they were adjacent to each other, it could not work if inserted the wrong way.
From there reach inside and feel for the back of the switch box. There are 4 plastic clips, 2 on each side. Squeeze them in to release them. Push on the switches from the front, and it will release into the open section where your hand/arm is. Then you can pull it out the side, and release the 2 wiring harnesses on the back.
I would assume the relays should go in 1 way, but generally those have a pin configuration so you can't plug them in incorrectly. It really comes down to where the pin assignments are. If it's a 4 pin relay, and the coils contacts are diagonal from each other, then it wouldn't matter how you inserted it. But if they were adjacent to each other, it could not work if inserted the wrong way.
Mounce
Member
Pull the dash trim to access the switch, not sure if it's built in to the headlight switch and dimmer and such or not, been a while since I was inside my dash. and yeah, the relay will work either way.
Thx Blckshdw. I was hoping that was the access way, and that it could be pulled out through the side. Mounce, my switch appears to contain all of the light controls on the same plate/panel. Blckshdw and Mounce: As far as the relays that I've pulled/installed, they've all been 4-pin rectangular, and they fit either way - I just didn't know if they operate correctly in either orientation.
Mounce
Member
Didn't see your post before I posted Blckshdw, wasn't aware that you could get to them from the side. 
As for the relays in the under hood fuse box, the normal little rectangular ones work either way, the poles are diagonally pinned.
As for the relays in the under hood fuse box, the normal little rectangular ones work either way, the poles are diagonally pinned.
I actually bought and installed a new relay. I figured if it wasn't the culprit, I'd least have a spare on-hand now. The fuse visibly looks good - I didn't check it with a VOM. So I guess that leaves me with the switch itself, or a loose/broken wire somewhere in the circuit.
Mounce
Member