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LAID OUT TIRE FRYER
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Discussion Starter · #1 ·
My dad's 06 dmax was hooked up to our trailer and it will no longer power up the trailer,also the third brake light does not work, or the trailer brakes. i can slide the controller over and it will brake hard, but i get nothing by just pushing the brakes. even when its unhooked i would get a -- reading from the controller, now i get nothing. i checked the third brake light bulbs and dont see breakage in either bulbs, but i will throw them on tester to see if the work. just seems kind of weird that they are both out. thanks for any help.

Edit: Ok fixed the third brake light. the veh chmsl fuse was bad, now i have trailer brakes. but i still dont have power going to the wire that gives juice to the trailer.
 

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Still use a simple test light. I turn on the lights and 4 ways and turn get each terminal to see if there's juice coming to the trailer. Just make sure you don't let two terminals touch each other. Have someone step on the brake as you test that connection. Here, we're just trying to see if it is the truck or trailer.

Is the trailer plug in factory or aftermarket? Is the brake controller "shop" wired into the truck, or was the GM jumper Z85 wiring harness used to plug in? Check all these connections to be sure they are good, especially if any are exposed and touching another wire on metal.
 

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What was the outcome on getting power to the trailer?

I have an '03 K2500. Fuses are good, connections look good. All lights work. No power to trailer hot wire on 7 pole. ie all lighting is working, ground is good, brakes work, just no power coming to hot wire.
 

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LAID OUT TIRE FRYER
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Discussion Starter · #4 ·
What was the outcome on getting power to the trailer?

I have an '03 K2500. Fuses are good, connections look good. All lights work. No power to trailer hot wire on 7 pole. ie all lighting is working, ground is good, brakes work, just no power coming to hot wire.

No i havent got it fixed, were probably going to take it to the dealer. The only thing i could think of is that recently my dad lost the boat trailer at a low speed cause he forgot to install the lock after he put it on the ball. When it came off it hit the 7 pin forcing it out of the hitch and bending the mount up. We might talk to our mechanic and see how the wire gets power. It might be a fuse up under the hood. I will let you know if i find out.
 

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LMK. This is driving me nuts.
 

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Found the answer. Posting it for reference. Need power to your trailer via the always on power lead in your 7 pole connecter?
"...
Before you start going crazy.............

To power up the pin in the trailer connector
(for trailer battery charging) you MUST intall
a maxifuse in Stud #1 slot in the underhood fuse
center. There should be a plastic plug already
in place which you will have to remove and insert
a maxifuse....................

Check out this official GM "Upfitter" document:
http://www.gmupfitter.com/publicat/2004_BB/2003_Beyond_LD_Electric_CK.pdf

I wish I'd found this earlier! Complete electrical diagrams and explanations. Page A-22 says you must install the fuse to activate the battery feed to the trailer connector.
..."

enjoy
 

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LAID OUT TIRE FRYER
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Discussion Starter · #7 ·
sweet i will have to try it out. it used to work, so maybe the fuse went out on that maxifuse.
 
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