im looking to jump my fogs and brights together so that i can have both on at the same time when the brights are activated, but only the fogs when my fogs are on. i was looking at the schematics, im not really sure which relays poles to jumper (using a diode to give me the result i want) anyone accomplish this? any electrical techys out there?

 

connentor c3 (white) under hood fuse block

B3(terminal)
TN/WH (tan wire with white stripe)
1969
Headlamp High Beam Relay Control
F11(terminal)
D-GN/WH(dark green wire with white stripe)
1317
Fog Lamp Relay Control

connect doide from b3 -> f11

terminals are marked on back of connector

 

dude thats incredible thanks, i was looking at the relays under the hood, but the low current sides were signaled by two diffrent voltages .6 and 11.

so to be clear you want me to jumper at thw connector not the relays?

 

yes at the connector. you need to pull up the fuse block and you'll see the connectors im talking about. theres one small and three big connectors. the big one to the left should be white. and thats where you'll find the terminals to tap.

 

those control wires should show ground when activated. the pcm/bcm controls ground to help the longjevity of contact in the computers.

what ever little voltage it might show when not activated is back feed throught the computer.

 

cool how do you know this? have you done it before?

 

hmmm..... I did that exact lighting mod on my C5 using a switch and a relay, but hadn't really thought about it for the C6. Between the HID's and the SilverStar fog bulbs I put in it just didn't seem needed, but since when is need a prerequisite to mod

Would you happen to have a Radio Shack part number (or recommended rating) for that diode.

 

thats the thing its a tiny diode for like 1 or 2 amps so i dont think it could handle the current load of the high current side of the relay

 

Hope it doesn't pull too much current and heat up the circuit with highs, lows, and fogs all on at the same time.

Keep me posted please if you get it working like you want it to.

Thanks

 

the fogs would be powered by the brights for the moments when i click the brights on, its not like i would drive like this

 

I was thinking of when I drive long distance and there is a need for all of them on at the same time for extended periods of time at night...that would be nice.

 

I'll have to look at the schematics in my manuals when I get home from work, but if circuits 1969 & 1317 are on the low power side of control relays, then this just might be as simple as it sounds

Just FYI, you can click here to see a very basic schematic of how I accomplished this on my C5. I used the + supply to the high beams to pull in a relay that then turned on power going from the accessory power wires to the fogs. The relay was there to do what the diode would be doing in this thread, make sure the fogs came on with the brights, but not the brights when you only wanted to use the fogs.

 

Looking at these schematics:

Fog Lights

Headlights 1of2

Headlights 2of2

If I'm reading them right.....

When the BCM wants the high beams to be on, it grounds circuit 1969. By looking at the print, circuit 1969 will ALWAYS have +12V on it.

When the BCM wants the fogs to be on it supplies +12V to circuit 1317. 1317 is the supply side of the already grounded relay 38.

So.... If we were to jumper C3/B3 to C3/F11 we would be connecting the always hot 1969 to the supply side of relay 38, which means the fog lights would come on and stay on, forever. Right? Am I missing something?

I still think we can make this work. If we used either circuit 711 or 311 (C1/D4 or C1/C4) as the supply instead of 1969, then the fogs would only come on when the high beams were actually energized.

How does that sound?

Unless someone torpedos my logic, maybe after I get some sleep I'll hook up my amp meter in series from 711 to 1317 to see if it works and measure the current (which shouldn't be much at all to pull in a relay).

 

i did try that and my fogs and brights were always on with no siwtches activated

 

I knew I was missing something this morning. I guess it was the fact that the high beams would also come on as soon as that jumper was installed.

I'm still 99% sure I can make this work. Some time in the next few days I'll make the time to do some experiments. I might even take some pics along the way, so you may want to subscribe to this thread

 

i am subscribed arent I?

 

oh and im looking forward to it very much

 

i looked up the schematics. and i found i was wrong about the computers only switching ground. the bcm switches b+ to control the fogs. what you want to accomplish is still easily possible, with a little more work useing a relay.

still using the b3 and f11 terminals.

if your familur with relays you know the terminal layout.
85, 86, 87, 87a, 30. (5 terminal relay)

connect:
85- b3
86- battery power
87- battery power
30- f11
87a- not used

 

hey Markcz wanna give this a try? im busy all week

 

Does the forum send you an email when someone makes a new post? If not, whenever you make a new post look at the 'additional options' at the bottom of the reply area. Or, just above post #1 click on 'thread tools', then 'subscribe to this thread', then pick how often you'd like to get an email. Even if you choose not to receive emails you can still subscribe to the thread, then if you click on 'User CP' in the forum toolbar all of the threads you subscribe to that have new posts since your last visit will be displayed. At the bottom of that list you can click on 'view all threads' and see everything you've ever subscribed to if it has new posts or not.

That looks like it should work However, you'd be grounding an aftermarket relay through the internal logic of the BCM. I'm sure it can probably easily handle the minute amount of extra current going through the coil side of a relay, but I'd rather not chance wiring it up that way with 70k left on my GMPP.

The power side of the high beam relay 39 is pretty much already doing the exact same thing. I plan on tapping one of the wires going directly to the high beam bulb as my +12V source for pin F11. All I need to decide is if I want to use a diode or a relay to make sure the circuits STAY separated. Right now I'm leaning towards a relay (call me old fashioned, but I trust them). I was also thinking about installing an on/off switch so the mod can easily be disabled if needed.

I'd hook it up like this:
coil pin 85: circuit 711 or 311 (depending which I can find and easily tap)
coil pin 86: ground
switch pin 87: fused battery +
switch pin 30: circuit 1317

Most definitely If I can't get to it Wednesday (which I guess is today ) I'll make the time on Thursday.