Trailer brakes only work when controller is overridden

[mikerr24]

Last week i had googled possible reasons why my trailer brakes would only work when i slid the override switch on the controller. i read many different suggestions on several different GM forums. first off, thanks to youtube i learned that GM now requires the truck owner to hook up those two wires under the hood to the studs by the fuse box and provide your own fuse(s). not a huge deal but definately an inconvenience, someone "old school" without internet would be out to lunch trying to figure out why their controller wasnt working after hooking up the 4 wires under the dash. in my case, i thought i had it all figured out, i triple checked that my controller was hooked up correctly, i had already hooked up the 2 wires under the hood and provided the fuses, then checked with a test light for power, so i knew they were working/correct.. AND the controller still seemed to only give me trailer brakes when i slid the override switch. with a test light i determined that i wasnt getting juice to the brake switch wire under the dash. i was developing gray hair by the second, getting more and more frustrated by the second. i get the bright idea to go purchase a new controller, (was hooking up a used controller that i did not know for sure if it even worked). so i hook up the new controller with same non-working results. i checked all the typical fuses that were suggested through the many google searches i did and they all seemed fine. eventually i started checking every single fuse whether i thought it "could" have something to do with it or not, and i stumbled onto fuse #43 and sure enough she was fried. i replaced it and bingo!! problem solved... moral of my rant, almost every post i read it only talked about the 2 "stud fuses". non of them said anything about the possibility of any other fuses and there were alot of posts with the same exact issues as i was having. so i hope this helps anyone else who may be having the same issues as i was having. btw, the above story was for a 2008 silverado 5.3 with tow package.

[BlackZ71Silverado]

You should have read the directions for the install that come with the controller. Much easier that way. I know the ones that came with mine were very clear.

[SouthCo]

Thanks for posting and glad you got it worked out. You've got an aftermarket controller right? I've got the factory tow package with built in brake controller and it worked great both times I had a trailer with brakes. I didn't have to do anything under the hood.

[MikeNH]

Thanks for posting and glad you got it worked out. You've got an aftermarket controller right? I've got the factory tow package with built in brake controller and it worked great both times I had a trailer with brakes. I didn't have to do anything under the hood.

 

 

Unless your dealer hooked it up the wire and fuse for 12V supply for the battery is not hooked up.

[latreille89]

I had the same problem trying to figure out why I had no power to the controller, finally watched an install video on a Silverado and saw the 2 posts. Found the wires, hooked them up and luckily I had the fuses already there. No more issues, works excellent!

[Coolmaker]

Thanks for posting and glad you got it worked out. You've got an aftermarket controller right? I've got the factory tow package with built in brake controller and it worked great both times I had a trailer with brakes. I didn't have to do anything under the hood.

 

 

Unless your dealer hooked it up the wire and fuse for 12V supply for the battery is not hooked up.

 

 

 

My 2012 came from the factory with the 12v battery wire hooked.. It has the factory built in controller......

[mikerr24]

You should have read the directions for the install that come with the controller. Much easier that way. I know the ones that came with mine were very clear.

 

 

At no point in the directions did it say to check the #43 fuse OR anything about the need to hook the 2 wires the the posts under the hood. in my 06 i didnt have any issues, basically plug and play so logically thinking, why would something newer be more difficult to hook up.... bottom line is its now working fine and i hope my post helps someone with the same issues.

[latreille89]

You should have read the directions for the install that come with the controller. Much easier that way. I know the ones that came with mine were very clear.

 

 

At no point in the directions did it say to check the #43 fuse OR anything about the need to hook the 2 wires the the posts under the hood. in my 06 i didnt have any issues, basically plug and play so logically thinking, why would something newer be more difficult to hook up.... bottom line is its now working fine and i hope my post helps someone with the same issues.

 

 

Agree, the instructions don't know your truck is a Sierra or Silverado. Thanks for helping others.

[MikeNH]

Thanks for posting and glad you got it worked out. You've got an aftermarket controller right? I've got the factory tow package with built in brake controller and it worked great both times I had a trailer with brakes. I didn't have to do anything under the hood.

 

 

Unless your dealer hooked it up the wire and fuse for 12V supply for the battery is not hooked up.

 

 

 

My 2012 came from the factory with the 12v battery wire hooked.. It has the factory built in controller......

 

 

Mine has the factory controller too but they didn't hook the wire up.

[tanked_darren]

There is an awesome how to around here telling you how to hook up after market trailer brake controller and trailer power wire as well.

 

I've noticed over the course of 5 years the models we bought at work some of them had trailer power hooked up (with fuse installed), but always you have to hook the "controller" wire up.

 

Yes, thank god for the internet, feel sorry for old school guys who probably would never be able to figure it out.

 

here it is: http://www.eworldz.com/truck/gmt900.pdf