Wiring Questions

richscorvettes · December 5, 2002

I have two questions concerning wiring on a 2003, 2500HD that I hope you folks can help with. I've searched the forum for old threads but not found anything. I wasn't certain which section of the forum to post this and hope this one works.

I am looking for a place to hard wire a radar detector. In some cars there is an accessory circuit for this purpose but I couldn't find anything in the owners manual on this. Could the cigarette lighter line be used, for example?

I also want to add lights inside the pickup bed and wondered where you would suggest taking the feed from. The truck has a hard tonneau cover and I can use some light in the bed. Can I tap off of the parking circuit for example?

I get the impression that the wiring is a little different in these trucks and don't want to mess anything up. I would appreciate your help. Thanks.

Rich Lagasse

Shaners · December 6, 2002

I believe the cigarette lighter and power outlets are always hot. That would mean you would have to manually turn off your detector or it would be a constant drain on the system.

As far as lights in the bed you could check with a truck cap dealer, or an RV dealer for suggestions. If you want to run the lights in the bed only at night when the headlights/parking lights are on then you can either tap into the trailer wiring provisions or the fifth wheel harness (if you have that option). I would think that you would want a "switched" curcuit for the bed lights, so that you don't accidently leave them on and drain the battery, so either of those options would be OK.

If you have the truck camper/fifth wheel harness option, there may be a full time "hot" wire in that harness, so that you could run lights in your truck camper and pull the power from your truck batery. Looking in my owners manual it says the "red" wire in either harness is the "battery feed". In my 2001 manual the info is on page 4-79. Other wise you could tap into the brown wire which feed the taillamps.

silverado man · December 6, 2002

To hard wire my radar detector i just squeezed the wire for the dectector in between a switched fuse and the terminal in the fuse box. And for the lights in the bed you could get a niffty little push switch so that when you open the tailgate the lights turn on. I beleive there is a hot wire that goes to the wiring harness for trailor lights or if you don't have the trailoring package there should be a wire loom around the spare for you to tap into. Or you could just run a hot wire from the battery and hook it up to the switch. Hope this helps some.

BlueRado · December 6, 2002

Rich, don't know if this helps, but I have a switched lite on my ARE topper, and the dealer ran a fused ring-spade harness and wire from the + battery jumper terminal along the frame and up the taillite access area to the topper.

Of course, in this case you would need to feed thru the firewall, but I think there is probably one feedthru for this purpose. I would expect you'd want to rig it to be switch operated, like others have mentioned.

Also, if you haven't already, you might contact one of our preferred vendors, JP Customs. He might be able to point you in the right direction if he doesn't have anything.

Keep us posted how you solve it!

richscorvettes · December 7, 2002

Thanks for all the great suggestions. I'll look for sources in the fuse panels for the detector. It should be easier than trying to tap into a line since it's tough to get at those. I actually need one switched source (for the radar detector) and one constant for the TV that works with the camera I installed on the car trailer. Hopefully, I'll find both there.

For the bed lights I like the suggestion of using the trailer wiring although you are right about the potential to leave a light on if the power source is constant. It would be great if I could tap into the outside rear cab light dash switch but trying to gain access to these wires is almost impossible unless you are a contortionist and I lost that flexibility a long time ago.....

Thanks again and have a great holiday season.

Rich Lagasse