Wiring In-Bed Trailer Wiring 12 Volt Power to a Switched Ignition Source on a 2004 Chevy Silverado

Updated 03/19/2013 | Published 03/14/2013

Products Featured in This Question

Starter Solenoid - SPST - 12 Volt - 100 Amp - Continuous Duty - Grounded

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10 Gauge Wire - Blue Primary - Per Foot

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Pollak Circuit Breaker - Cycling/Automatic Reset - 40 Amp - Straight Mount Bracket

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Question:

I installed a new RV plug in the box of my 2004 Chevy HD for connecting to my camper. My problem is that I have 8 wires available and the RV plug has seven slots. The eight wires are: LT TRN RT TRN RR LP B/U LP 12 Volt Aux Power Brakes GRND Both the 12 Volt and Aux were heavier duty wires. The 12 Volt is hot all the time, whereas the Aux appears to have no power. If the Aux wire were to be on only when the truck is, I would prefer to use that power source rather than the 12V wire as I will eventually forget to unplug the camper and drain my truck batteries. Is the Aux a power source, and if so, how do I get it to provide power?

asked by: Peter

Expert Reply:

The AUX can be a power source if connected to the battery. Normally on a 7-Way, the center pole is either AUX or reverse lights. I recommend using the center pole for the reverse lamps since you can wire the 12 volt hot lead to be on a switched ignition source if you wanted.

Basically what you would do is find a 12 volt power wire that is only hot when the truck is on. That way it will turn off when you shut off the key. One way to do this would be to use a battery isolator, # PK5231201. What you would do is attach a wire from the positive battery terminal on the vehicle, go to a 40 amp circuit breaker, # PK54540, then to the isolator. The small terminal in front of the isolator would be connected to a 12 volt ignition source. Then on the output side of the isolator, run it to the 12 volt circuit on the 7-Way. I included a diagram that shows how to wire it in this manner.

You will also need some 10 gauge wire, # 10-1-1, which is sold in 1 foot increments.

expert reply by: Michael H