01 Tahoe Fog Light Install Question

[MadDogDelpho]

No, No, No and NO! You DO NOT

How do you really feel?

 

[05Single]

lol it's fine wired the right way with a relay, just basic oem fogs. Not some crazy 200w light bar or KC daylighters.

 

[huffster329]

No, No, No and NO! You DO NOT wire fog lights directly to your headlights and you dont wire the fog lights directly thru your fog light switch. Here is why, The switch wired directly in series with the fog lights means all current passing thru the lights passes thru the switch. Most likely the switch isnt rated for that kind of current. What you should have is really 2 electrical circuits. The Fog lights wired to the normally open set of contacts of the fog light RELAY and the other side of those contacts wired to your 12v power source. All of that wiring is probably aready at your fusebox from the factory. Then you have the control circuit portion of the fog light circuit. The fog light switch is wired in series with the coil of the fog light relay circuit OR the switch gives a signsl (12v+ or possibly negative) to the BCM and ultimately the BCM gives a ground to the coild of the fog light relay. Id have to look in my schematics to tell you for sure how the factory does it. Im 1000 miles almost from my schematics currently.
Bottom line, you hook up light switch in series with the lights and you run the risk of melting wiring and/or a dash fire. There are basic wiring principles for a reason, especially in autos and the risk of fire or severe damage is great when you cut corners in auto wiring. Dont do it.

That's what I'm trying to do, wire the fog lights the correct way through the relay. Just as it would be from the factory. I really don't want to melt any wiring or cause a fire. When you get back to your schematics could you find out where exactly I need to wire into in the power center? I did find an old thread where he tied into terminal 87 (purple wire) under the relay, got the BCM reprogramed, and was good to go. Here's the thread I'm speaking of. http://tahoeforum.com/showthread.php?t=524905
I don't want to start messing with anything until I know exactly what I'm doing.

 

[05Single]

The options I said are also "the correct way"
I wouldn't tell someone to do something if it will catch fire or cause harm .

 

[huffster329]

What I meant by the correct way was exactly how it would be from the factory. That's the route I was hoping to go. I didn't mean to sound like your way is the wrong way.

 

[rockola1971]

I've heard people wire them to their parking lights too. I've found prewired vehicles are hit and miss.my 05 Silverado was not prewired for fogs

Why would you even mention this? How exactly is this the "correct way" ? Dont you think the factory would have done it this way if it was safe and met automotive elctrical standards?

 

[rockola1971]

I would first verify that the fog light relay is in the fusebox. If it isnt then acquire the correct relay. Put a meter on the normally open contact terminals in fusebox to see if one side is hot (12v). Test inside oem fog light switch to see if the switch energizes relay and closes the contacts. If not then that will need to be corrected. COuld possibly be a PCM program issue. Ill have to check my schematics to verify that one.

 

[05Single]

What I meant by the correct way was exactly how it would be from the factory. That's the route I was hoping to go. I didn't mean to sound like your way is the wrong way.

Yea I understand what you were trying to get at. was just reassuring you that it's fine to use the other options without getting discouraged by rockola.
I'm the same as you, if I can use an oem option I always try and go that route. But for fogs I've almost always hooked straight to the power source with a relay and inline fuse. Wrapped the wires in loom and nobody knows the difference. Just remember to turn them off when you park.
But I understand that you want 100% oem , but there's not much out there for 00-02, but sounds like rockola has your back.

 

[05Single]

Why would you even mention this? How exactly is this the "correct way" ? Dont you think the factory would have done it this way if it was safe and met automotive elctrical standards?

lol I never said this is the correct way, little confusion. I wouldn't personally do it this way , just said I heard of some doing it this way without issues.

 

[rockola1971]

One key problem with hooking up to the parking lights circuit is that there could be a situation where total load on that circuit with the addition of the foglights could exceed the amperage rating of the fuse that feeds that circuit which of course makes ALL loads on that circuit dead. I dont have my schematics with me so I cant say for sure what all those loads would be. This is why I dont play the guessing game and try not to reinvent the wheel when GM has already done all the engineering for us. (Granted some could use improvement). Im not jumping on you 05Single, I just like to try to stay away from leading some of the less experienced (in electrical) from thinking its ok to "experiment" while they might be under the assumption that bad things cant happen. I dont want anyone here on this forum to be a Darwin award winner or end up on Google News with their K chassis flaming in the background. Its easy enough to use GM's engineering and even add any missing components that werent an option on anyones specific K chassis.