Wiring Guru's - Need Advice

leverlution · August 22, 2010

Not sure if this is the right forum or not, mods please move if necessary. I have been raging a war to add Fogs to my 2010 since the day I bought it. Long story short, my wife is 4'11 so power seat was necessary, and didn't have much choice. I drive in the snow for hospitals, and travel deep in the mountains on tight roads in winter time (heavy fog and snow). I never really thought it would be a big deal until I tried to add some. Anyway, these are my problems: GM doesn't sell the fog light kit in Sheer Silver, and I just have a problem buying one in say white or red, and paying to have it repainted because I have a different (Common) color. I don't want to cut any factory wiring, or drill the firewall, or cut any rubber firewall grommets, making wiring a switch and fogs pretty hard. I see too many "rigged" vehicles at work, and want to leave this one clean. Lastly, I don't have money laying around for a light bar and wireless switch. So, these are my solutions, and I need some wiring guru's to tell me if any will work, and which would be most ideal.

All ideas involve Hella 500FF's laying around the garage, and bolting them to the brackets behind the bottom of the grill.

I have an OEM headlight switch with fog light button in my garage. I also have a delphi terminal from the B5 port of a GMT900 truck WITH factory fogs (salvage). I could swap the switch, plop in the terminal, and run the wires to the Hella's for a "factory" wiring setup. The terminal got a little bent up during removal, but MAY be salvaged. Dealer and I went through all the boxes and couldn't find a replacement anywhere. Not sure that this terminal will work.

I have an HID kit on the way (I hope anyway) from DDM tuning. 35W, 4500k H11 kit, with a relay harness. The other idea I had was to tap into the HID harness somewhere, engaging a relay on a second homemade harness, running 12v battery fed power to the fogs anytime the low beams are on. I don't like running fogs unless I need to, but this involves no OEM wiring cutting or anything of the sort. Problem is, I am not sure where in the circuit for the HIDs that I can tap into, send power to a relay for another circuit, and still have the HIDs work properly. In other words, if I tap into the HID harness between the relay and the OEM headlight switch (before the HIDs are activated), I may "transfer" the electricity to the fog circuit with not enough power still going to the HID relay to activate that circuit. If I tap into the HID harness between battery and balast, the balast no longer gets 12v, and may redirect all the power to the relay.

Not really sure how to make this work, and ANY advice would be awesome. Thanks.

gregrocks89 · August 23, 2010

Not sure if this is the right forum or not, mods please move if necessary. I have been raging a war to add Fogs to my 2010 since the day I bought it. Long story short, my wife is 4'11 so power seat was necessary, and didn't have much choice. I drive in the snow for hospitals, and travel deep in the mountains on tight roads in winter time (heavy fog and snow). I never really thought it would be a big deal until I tried to add some. Anyway, these are my problems: GM doesn't sell the fog light kit in Sheer Silver, and I just have a problem buying one in say white or red, and paying to have it repainted because I have a different (Common) color. I don't want to cut any factory wiring, or drill the firewall, or cut any rubber firewall grommets, making wiring a switch and fogs pretty hard. I see too many "rigged" vehicles at work, and want to leave this one clean. Lastly, I don't have money laying around for a light bar and wireless switch. So, these are my solutions, and I need some wiring guru's to tell me if any will work, and which would be most ideal.

All ideas involve Hella 500FF's laying around the garage, and bolting them to the brackets behind the bottom of the grill.

I have an OEM headlight switch with fog light button in my garage. I also have a delphi terminal from the B5 port of a GMT900 truck WITH factory fogs (salvage). I could swap the switch, plop in the terminal, and run the wires to the Hella's for a "factory" wiring setup. The terminal got a little bent up during removal, but MAY be salvaged. Dealer and I went through all the boxes and couldn't find a replacement anywhere. Not sure that this terminal will work.

I have an HID kit on the way (I hope anyway) from DDM tuning. 35W, 4500k H11 kit, with a relay harness. The other idea I had was to tap into the HID harness somewhere, engaging a relay on a second homemade harness, running 12v battery fed power to the fogs anytime the low beams are on. I don't like running fogs unless I need to, but this involves no OEM wiring cutting or anything of the sort. Problem is, I am not sure where in the circuit for the HIDs that I can tap into, send power to a relay for another circuit, and still have the HIDs work properly. In other words, if I tap into the HID harness between the relay and the OEM headlight switch (before the HIDs are activated), I may "transfer" the electricity to the fog circuit with not enough power still going to the HID relay to activate that circuit. If I tap into the HID harness between battery and balast, the balast no longer gets 12v, and may redirect all the power to the relay.

Not really sure how to make this work, and ANY advice would be awesome. Thanks.

I wouldnt tap into your ballast but if a person would tap in to them touch the wiring you plug into your oem wiring and the ballast. anything after the ballast your just gonna be wasting your time and cuasing stuff to catch on fire. You got 12v entering your ballast and 22,000v leaving your ballast. So i wouldnt touch anything leaving it. If your gonna tap into your Ballast wiring, do go before the it enters the ballast tho.

Also as for your fog lights the easiest way is to get them mounted. Run your two ground wires into a ground somewhere in the front. Take both power wires into a butt terminal splice with one leaving to a switch you can mount anywhere in your truck. You will have to drill thru your firewall. Terminate the wire to the normally closed position on your switch. Then take a wire from your switch on the normally open side to a inline fuse. Your fog lights will say the max amperage on them so use that fuse size. After leaving your inline you can either go an auxiliary power post on your fuse block or your battery post.

leverlution · August 24, 2010

Thanks for the input. My goal is to try and avoid drilling into the firewall or cutting OEM wiring. I know I can't use anything after the ballast, that would be asking for trouble. Not to mention I believe they use a special wire, but I could be wrong.

Anyway, if I tap into the HID harness between the OEM wiring and the HID relay (after the harness connects to headlight plug, before the relay for the HIDs), would the fogs AND the HID relay's both kick on or would all the electricity just follow the circuit with the least resistance, leaving none to go to the other relay? I really don't want the fogs on 24/7 (I was eventually going to do an HID upgrade to those free forms), but if this is my only option, than so be it. It's the only thing I can think of, other than replacing the switch with OEM switch and hoping that terminal I got isn't too far gone.

gregrocks89 · August 26, 2010

Just run 14awg wiring into your fog lights from the oem harness. Electricity will flow thru both. But yes once your headlights turn on those will turn on to unless your gonna have a switch. You could always have a relay hooked up to the highbeam switch and everytime your highs would turn on the fogs will to. I havent done that before so im not to sure how it set it up

leverlution · August 26, 2010

Awesome, thanks. I don't wanna cut the factory wiring, and I'm only gonna use em in bad weather(which I should see a lot of) so highs are out. I did source 2 more delphi terminals, so I may do an oem setup with the hellas. If I can hit a relay off the HID harness and not stop the lows from kicking on, I may go that route. Not sure yet. Either yellow 55w halogens and run off hid harness or 55w yellow hids and run oem switch and wiring. Thanks.