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EVRYTHING 12v Power at Trailer plug maxi fuse fuses

dvc

Charter Member
SM 2003
Full Member
Joined
Feb 14, 2002
Messages
134
Location
San Jose
I was hooking up my electric brake controller, no problems, until I touched the cable leads to the metal brake arm. Total accident because I was just setting the cable down.

Here is the sequence of events:
1. Hooked up the Av Trailer Wire Harness
2. Trimmed the ends to match it to the Prodigy
3. I followed the directions on the Prodigy to match up the wires
4. Before making the final connections I just twisted them together
5. Hooked up the controller, and it worked great
6. Unhooked the wires and measured to trim them
7. Trimmed the wires and mounted the brackets
8. I went to hook up the new wires trimmed that is when I touched the hot lead on the brake pedal. It sparked.
9. I went to check to make sure the fuses were ok and they are all fine
Went to hook up the controller and nothing, no power.

I thought the controller somehow got fried, but it was not hooked up so I went to exchange it, which they did, hooked up the new and nothing.

What do I do, I have tried everything, am I missing a fuse, I check inside the main fuse box, the one inside the driver door, had OnStar do a computer check, and nothing. Am I over looking something, could have the power block under the dash been damaged in any way?

Helppppppppppppp if you can.

Thanks
Dennis
 
Dennis, no specific advice here but check in the electrical center under the hood, plenty of fuses there.
 
I think you hit it right on the head with the underhood fuse box. That is the location for the fuses for brake controller and other trailer circuits. I checked them out the other day while detailing a bit under the hood.

Sounds like a good case for the pre made harness.
Just plug in and no blown fuse problems. ;)
 
Hey guys,

I tried the under the hood fuses. The 40 amp fuse was ok, and the other trailer fuse also showed no problems, that is why I am so confused.

The reason you can't put a plug on both ends it because each controller hooks up differently in terms of color coding. The Controller would need to pre-make connectors for every make and model and that is not pratical.
 
Dennis, have you got a multimeter - check the leads for signal, if you don't have one, Sears and Radio Shack can fix you up.
 
I guess Orboaters point was - hook up the controller first, then plug it in - no risk of sparks . . but what you described should not have damaged anything except a fuse! I'll add my bet to it being there somewhere - and tracing it with a test light or multimeter is probably the way to go - sometimes a quick look can miss a blown fuse.
 
Hey guys,

Thanks for the help, I solved the problem. The patch block under the dash is fed by Stud 2 in the Electrical Box in the engine bay.

The so the 30 Amp fuse needed to be replaced. Stud 2 according to the manual does not feed anything. Go figure.

dvc
 
dvc said:
The so the 30 Amp fuse needed to be replaced. ?Stud 2 according to the manual does not feed anything. ?Go figure.

dvc

Hold on there cowboy, are you saying there is a 30 amp empty circuit available under the dash? ?I'm not questioning your input, I just want to clarify. ?If so, I've got some serious plans for that circuit.
I am on the verge of adding several electrical items to the truck, and I would be very pleased to know of a free 30 amp circuit available without punching through the firewall.

Thanks in advance for a clarification. (read "reassuring pat on the head." ;)

helmet
 
A free 30amp circuit? Is this posible ??? If all it does feed is the electric break I could use this. I'm not planning on installing one in the near future but an extra 30 amps of power would be very useful. I haven't looked for it yet, if anyone knows which one it is that would be easier on me.
 
Hey Helmut,

I went by the dealer on Saturday and confirmed, Stud 2 powers the plug-in block under the dash.

Pull the cover and see if any of the relays will cause a problem but when the fuse was blown, I did not experience any problems and no warning lights came on, these may not have critical systems going through them, but check inside the cover to see what eac h post handles.

I hope this helps.

dvc
 
I have some ideas for some 12v fun on the trailer plug. But I need power when the Av is off. Are there any hot leads in the trailer plug? Not planning a huge load, but curious. Also, if someone can give me a wiring diagram for what all the leads are that would be appreciated. Don't think I've seen this info on here, but if it is, I apologize.

Brendan
 
Nevermind. I should have read some of the posts in the "12v powerpoint outled in bed" thread. I found some info in there that will help me out. But I could still use a wiring diagram for future use...

Brendan
 
Brendan,

Yes there is power available from the Green power plug that plus in underneath the power distribution box on the drver's side fender.

You will need to remove the fender brace on the driver's side so you can remove the cover and box that surrounds the distribution console. After you remove the coverings, there are a set of tabs that hold the distibution console down. These tabs are located on the driver's side fender. Press these tabs and tilt the distrobution center towards the engine. The Green plug is the one that will be in the upper left corner of the distibution console while looking at the bottom. Loosen the screw that holds this plug in place. While looking at the wiring side of the plug, the pin area that would be the very last one on the lower row is available for 12 v while the ignition switch is in the on position. You will need to add a pin to the plug as there is not one supplied factory. You will know you are looking at the correct pin location if you see two blue wires going into the pin that is directly above the one you want to use. I removed one of the pins and wires from the trailer harness that came with my truck since i will not be using it.

Hope this helps.

Mike Henderson
 
brmiller, I may have an answer for you. Today I picked up a 12v power adapter for my hitch plug, in order for it to work you have to install a 40A Maxi-Fuse in Stud #1 location in the underhood electrical center. Now I have power to the adapter all the time. Now I don't know if this will effect the boat trailer lights will test it tomorrow. :0: I'll also check to see what pin is live and post back.
 
I'll be looking for your response too . . .

My first reaction was that it must be in the manual, and indeed, they indicate that the 'red' wire is +12 volts. Doesn't say anything about what pin this is or if an extra fuse must be installed to make it work. Real helpful eh?
 
Phantom said:
brmiller, I may have an answer for you. Today I picked up a 12v power adapter for my hitch plug, in order for it to work you have to install a 40A Maxi-Fuse in Stud #1 location in the underhood electrical center. Now I have power to the adapter all the time. Now I don't know if this will effect the boat trailer lights will test it tomorrow. ?:0: I'll also check to see what pin is live and post back.

what adapter did you get? was it the GM adater? also isnt the power a 70 am p circut leading back ?
 
BlackAV, yes it is the GM adapter part # 12490923, in the instruction it does say that the max load of any electrical equipment should not exceed 20 amps.
 
Phantom said:
brmiller, I may have an answer for you. Today I picked up a 12v power adapter for my hitch plug, in order for it to work you have to install a 40A Maxi-Fuse in Stud #1 location in the underhood electrical center. Now I have power to the adapter all the time.
This sounds good--I may just go this route mysellf. Before, I was going to get all the connectors and wire it up, but this is so much simpler. Someone posted that they got the part (a Cadillac Escalade accessory, in fact) at the dealer parts counter ($35 list, I think). Surely this part can be made cheaper since the trailer plug is a bit of a standard--where did you get yours, or where can it be found cheaper?

Off to "Trailer World" tomorrow.

Brendan
 
Phantom said:
I got mine at the dealers for $35. Maybe GM Parts direct can get it cheaper. If you check out my photo site in album one you can see pics of the unit.
Yep--so it was you. I'll check out my local trailering shops and swing by the dealer if I have to.

Thanks for the pics--I had looked at that earlier and was convinced that was the way to go.

Brendan
 
Okay had to wait for the rain to stop.

The pin at 1 o'clock is hot.

The pin at 7 o'clock in ground.

Trailer light are not effected, if you look at the 4 prong adapter their is no connection at 1 o'clock

See pic sorry for the bad quality.
 

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I have a problem with the right side trailer turn signal
blowing a fuse (under the hood) each time I plug in the wiring harness. I do not have that problem when using my other vehicle towing the same trailer. If I remove the fuse before plugging in the trailer wires then replace after connecting it works fine. Could the trailer not be grounding on the hitch?
 
r webb try another trailer, to prove the av first,, some trailers i pull will pop a fuse on 1 vehicle and not another.. seems like the clearance lights give more trouble than turn signals... sometimes to troubleshoot i will purposely plug in the flat four 1 pin at a time to test 1 circuit at a time.... believe in the av first and blame it on the trailer by trying out another trailer!!
 
br miller i'm just going thru what we both want, lots of amps back at the trailer plug area and not having to run extra wires. the 7 pin adapter only has 4 contacts in it from the factory for trailer lights, but if you pop off the back of the plug, you will see the big red is hot, but the big blue is not, that haresss is option z-82, and i just started a post about it be careful with the ground, shapeshifter was smart to remind ue that the ground should always be as big as the red,,, go read post, my z71 has z82,.... and hey, what you putting in back there???? im sneaking a 110 volt inverter in the storage box!!...........ps a trailer supply can supply the plug with contacts at all positions,,,ya know!
 
You may also want to check out all of the cables and connectors on both the trailer and truck. From your description it sounds like the problem might be when you are actually plugging/unplugging it. Maybe there is a loose or frayed wire, or a loose or bent contact. While you are plugging it in, it might be shorting or gounding out the line temporarily. I'm thinking this because you say it's fine if you pull the fuse while you are plugging in. It may be your other vehicle is more tolerant of a momentary short.

-- SS
 
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