Just wanted to revisit my problem-I need to tap into a 12 volt source with enought amps for my airhorns (20 amp fuse recommended). I would like to avoid running a line from the battery in the trunk. Already tried the P/S and jumpstart terminals-not enough amps. Would one of the empty slots in the fuse box be ok to tap into? I could just put a female spade on the wire and plug it in to connect the relay.

If anyone has a wiring diagram of the fuse box, it would help. I feel silly having these cool airhorns, compressor, etc in the car without being able to use them.

 

Constant 12v or a switched source?

 

Either one would do. It is for the auxilary air horns.

 

You can grab a constant 12v at BCM C3 in that image...12v is red/black

 

Thanks for the info. I didnt even realize there was a fuse box in there. But I would prefer the box in the engine compartment, since that is where the relay is. It would save me running more wires through the firewall grommet.

 

I wouldnt pick up power at the BCM, in fact I wouldn't mess with the BCM at all. It has to be one of the most complicated and touchy modules in the car. It controls just about everything and they like to fail quite frequently. We've been slow lately, if I have time tomorrow I have a couple of things to do to the car anyway, I'll pull a schematic and poke around under the hood. I'll find you some place to pick up power.

 

Thanks, Aaron. I would really appreciate it.

New cars are so much trickier to work on than old ones.

 

I've gone to the BCM plenty of times to do remote starts in the newer Chevy's (that's your best place for power in the new ones), and I've yet to come across any issues whatsoever.

 

Let me guess you work at a stereo shop.

 

:)

Look at the new GM's- just about all of them lack a constant and a starter wire at the ignition harness, leaving you the BCM :)