7 pin plug, no power to backup lights

bmklawt · #1 03-25-2009, 08:06 PM

2005 Silverado
I am hoping I am just missing something, I was checking to make sure all the lights work on my new camper and I can not get the backup lamps to work.
I unplugged the camper and tested the center pin of the 7 pin trailer plug thats on the vehicle and I get nothing, is there a fuse I am missing, anyone have any ideas why this does not work. The reverse lights on the truck work fine.

Your help is much appreciated.

sassydog · #2 03-26-2009, 10:26 AM

The standard 7 pin connection does not include Backup lights. I think the center pin is auxilary power and is supposed to be hot but I can't remember for sure. I remember having to switch some wires to get them working on our '98 burb but not sure what we did. Seems someone told me there is a wire run for reverse lights on these trucks but I haven't looked.

j cAT · #3 03-26-2009, 04:10 PM

Quote:

Originally Posted by sassydog

The standard 7 pin connection does not include Backup lights. I think the center pin is auxilary power and is supposed to be hot but I can't remember for sure. I remember having to switch some wires to get them working on our '98 burb but not sure what we did. Seems someone told me there is a wire run for reverse lights on these trucks but I haven't looked.

on my silverado [tow pkg] their is a wire hanging with a plug on the end...since I don't have the back up lt need perhaps its this wire next to the plug socket....let me know..check with a meter .....

bmklawt · #4 03-26-2009, 06:45 PM

Thanks everyone for the help,

The center pin is the backup lights, the cover of the trailer 7 pin connector has the pin out molded into the cover.

I finally found the wiring schematic for the trailer wiring in the service manual and it does show a fuse for the backup lights under the hood. There is no mention of trailer wiring in the index of the service manual so I went through 200 pages of print twice and found it.
I went back under the hood and found fuse "TRL B/U" that makes perfect sense now.

I had checked that fuse earlier and it checked good, I also had looked in the owners manual for the fuse description but must have missed it, it is there.
When I check the fuse earlier with a fuse checker it checked good, after finding the info in the book I went back to the "TRL B/U" fuse and actually pulled it out, it looks good so I tested it with the fuse checker while holding it in my had and found that there must be a break in the fuse, it would show good intermittently, the fuse is not blown.
I think when I pressed the pins of the fuse checker into the fuse it would move it enough that where ever it is broke would make contact and show the fuse as good
I put an ohm meter on the pins of the fuse and it read open and when I jiggled the pins of the fuse just right I could get a good reading so I replaced the fuse and all is well.

10 hours of my life down the tubes because a fuse was bad

sassydog · #5 03-26-2009, 06:46 PM

Just put a meter on my '04 and the center pin is backup lights.
Started raining on me before I could get to the wire beside the 7 pin. I don't think there are separate fuse to the plug, so if your back up lights work on the truck you should have power to your plug. Camper plug may be wired differently too, wouldn't be the first time! Good luck!

sassydog · #6 03-26-2009, 07:31 PM

Great info to know thanks. I have found that the wire beside the trailer plug is for the third stop light such as on a camper top.

j cAT · #7 03-26-2009, 08:33 PM

Quote:

Originally Posted by sassydog

Great info to know thanks. I have found that the wire beside the trailer plug is for the third stop light such as on a camper top.

thanks for the feedback on this...
with an intermittent failure like that fuse I think he did a great job troubleshooting it properly..

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