yup im subscribed, i have a relay from my air horn install on my DD, would that work?

 

BUMP

 

As long as it has a 12VDC coil and contacts that close when you energize the coil it will work just fine.

I plan on doing mine later this evening. I'll take pics and post them as soon as I'm done.

 

I finally had the time to pop my hood and look around this evening. My original plan to use in-line taps on the wires would have worked just fine, if it wasn't so damn hard to get at the wires under the fuse box

I got it to work....



However, I need to run by Radio Shack tomorrow in order to pick up a diode and possibly one other part before I show anyone how to do it. It's so simple you won't believe it. If you want to do it as quick and cheap as possible, how does $1.49 and 10 minutes sound?

Stay tuned.....

 

If you want to make this work using the least amount of time and money possible, all you'd need is a diode and about 4" of wire. The wire needs to have the diode spliced into it, then installed between fuse box pins J4 and A4 with the end of the diode with the line painted on it facing pin A4. The top of the fuse box has the letters and numbers along the edges, kinda like the game Battleship. You'd be doing this, but the diode MUST be installed. DO NOT just hook up a wire between the two pins as I have in the picture, if you turn on your fog lights without a diode installed (or installed backwards) you can do some serious damage to your BCM. Consider yourself warned When energized the fog relay pulls 125mA of current (or 1/8 of 1 Amp), I used a 3A/50PIV diode, but anything rated 1A or more should work.

I did mine a little neater, and installed a fuse to protect the BCM just in case the diode decided to fail.

I started by gathering the parts I'd use:




The fuse taps were made for standard size blade fuses, we have the mini size blade fuses, so I needed to use a dremel to trim down the blade a bit so it would fit into the fuse box. I also had to straighten the folded end to make it fit better, then inserted the taps into pins A4 and J4.




To connect the diode, I used 1/4" spades that I pushed on to the ends of the diode, then put a drop of solder on to keep it from working loose. The diode MUST be installed with the white or silver line facing the fog relay at pin A4. DO NOT turn on youg fog lights (with the switch on the turn signal lever) until you verify that turning on the brights also turns on the fogs (to verify the diode is installed correctly):




Since the fog relay only pulls 125mA when energized, I installed a 2 Amp fuse in line with the diode to protect the BCM just in case the diode was to fail. A little heat shrink over the diode, a few more crimp on spade plugs, and this is what the completed jumper looks like:




The jumper installed:


You can ignore the add-a-circuit fuse tap installed in my box, that's how I powered my hidden radar detector


And the end result, all 6 lights on at once:




Fogs only:




If you use 'flash to pass' (or hit the unlock button on the fob):




How it works, and the potential problems if you hook it up wrong:

If you look at the schematics, what you're doing is tapping in to the +12V supply going to the right side high beam bulb (circuit 311) and using it to pull in the relay that turns on the fog lights (circuit 1317). If you were to just connect a wire between those two circuits, or install the diode backwards, when you energized the fog lights you would be trying to turn on your right side high beam bulb using +12V that is coming from the internal logic of the BCM. It may be able to handle the current, but I'm guessing that it can't. Please don't be the one to find out!

Now that I'm done modding the car I think I'm going to give it a much needed bath.



Edit: To make fogs come on whenever HEADLIGHTS are on....

Instead of using J4 to make the fogs come on with the brights you would use either L5 or L6 as the source (whichever is easier for you to get to). Don't use M5 or M6, that's the wrong side of the fuse.

 

great job, how small of a fuse did you use?

 

2 amps. I figured it was plenty big enough to not blow with just the coil energized, but hopefully small enough to go before the BCM was damaged if the unthinkable were to happen.

 

EXCELLENT write-up! Thank You!


This should be added to FAQ and/or made a sticky.


QUESTION on where to place the fuse please:

In the pics above which side of the diode does the 2 amp fuse go on please?

Does the fuse go on the side of the diode that has the silver line painted on the end of it?


.

 

I put the fuse on the anode side of the diode (without the line), but it really doesn't matter as long as the diode is installed so it will only allow current to flow from J4 to A4.

Just to clarify how I wired it:

Starting at pin J4 (+12V when high beams are on)
2 amp fuse
Anode side of 3A/50PIV diode
Cathode side of diode (the side with the line)
pin A4 (ungrounded side of coil for fog relay)

 

Thanks markcz! Way to GO! And thanks again for posting all of this!

 

No problem I just hope my mod fever goes back into recession again soon

edit: I added a link to the mod post at the end of the C6 FAQ thread

 

No, no, say it isn't so. Don't wish that on yourself, you'll only get old, dusty and rusty sitting around not modifying your car!


Get a moderator (or the one that authored the FAQ list) to add it to the body of the original post toward the top of the page so members who would like this don't miss it with it being at the bottom of the replies to the FAQ list.

Good job man!

.

 

Thanks Mark.

 

i wired it up just like illustrated, flicked the brights and all 4 lit up, turned the fog lights and nothing, tried that a few times, nothing. took the jumper out flciked my brights the right was out, replaced the fuse and the brights both worked. remebered the car must be on for the fogs to work, turned car on, and they worked.

hmmm what did i do wrong?

 

I suppose it's possible, however unlikely, to blow a 10A fuse without blowing the smaller one in the jumper, but that would assume something was wired up wrong. Since you said all 4 lit up when you initially flashed the brights, that doesn't sound like the case.

I'm guessing that your fuse element broke due to 'rough handling' when you removed the jumper. Again, not a very common thing to happen, but I don't see what else it could have been given the info you gave us.

Did you reinstall the jumper to see if the fogs still worked on their own after replacing the fuse?

 

nope i almost **** a brick when i saw my fogs werent working (car was off tho) so yea im going to use the spare 15A to try again, i dont have anoymore 10A fuses laying aorund

 

mark im very mad at you! grrrr now that it all works i want to change my fog lights to HID and put sylvania super white bulbs for my brights, happy?

 

Thank you markcz!

I've wanted to do this mod for a long time but never got around to it...you've made it simple enough that even I'll find time to get 'er done!

 

20 minutes start to fin here...

 

I already have Silver Stars in the fogs and 100W generics in the brights

I'm just patiently waiting for someone to flash their brights at me when mine aren't already on, then they'll see what bright really is

Glad you got it working

Part of being a modaholic is taking the opportunity to spread the disease whenever possible