Chevy with brake controller problem.

[sbodi4d]

Went to pick up my new Pup at the dealer yesterday, but they could not get the brake controller to work on my truck for some reason. I have a 2007 Chevy Silverado 1/2 ton new body style. I think they said they had power to the controller, but nothing back at the seven way plug. They told me there must be something wrong with the factory wiring harness, and to take it to a Chevy dealer to get it checked out. He said it would flicker on, but not stay on, so he thinks the controller is good, but I think it may be a bad controller. All I know right now is it is a Tekonsha controller. Not sure what model or anything, but they charged me $175.00 for the controller with installation.
Anybody had trouble hooking up a brake controller to a Chevy? The only thing on the truck that isn't factory is a Leer camper top that I had installed two or three years ago. The high mount brake light on the camper top doesn't work some times, but it works most of the time. The inside light for the camper top has never worked, but I was going to look at it sometime to see why. I don't think that has anything to do with the brake controller, but I have seen some strange electrical stuff before. Any input would be appreciated.

[Iraqvet05]

kaydeejay wrote:
Hmm, that's also news to me. When did GM start that link, it's certainly not so on my 2005?

Not sure when they started that...I'm guessing with the 2007.5 models. The 12v aux feed (like the controller 12v supply wire) is also not connected from the factory. Here is the info from the owners manual on the "battery feed" wire:

If charging a remote (non-vehicle) battery, press the
tow/haul mode button located at the end of the
shift lever. This will boost the vehicle system voltage
and properly charge the battery. If the trailer is too light
for tow/haul mode, turn on the headlamps as a
second way to boost the vehicle system and charge
the battery.

[RCMAN46]

"The red flag for me is the intermittent high brake light (CHMSL). That runs off the same feed from the brake switch as is used to drive the brake controller."


This is right on target. This is the light on top and back of the cab. If it is not working correctly then the controller will not work.

Also there will be no voltage at the 7way unless the manual lever is used on the Prodigy series controllers and with a high gain setting.

Get the CHMSL working correct and your problem will most likely be solved.

My 05 has two brake light switches. One for the regular brake lights and on for the CHMSL/trailer brake light. They have separate fuses so a short in the trailer does not disable the regular brake light system.

[kaydeejay]

Iraqvet05 wrote:

kaydeejay wrote:

Iraqvet05 wrote:
............ Also makes sure the tow/haul button is pushed in when you test it.

I'm curious - since when did the tow/haul button have any effect on how an after-market brake controller works?

Nevermind...it doesn't. I was thinking of the 12V battery charge feed for the 7 pin connector that is only energized with the tow button on.

Hmm, that's also news to me. When did GM start that link, it's certainly not so on my 2005?

[bikendan]

Iraqvet05 wrote:
Did the dealer add the fuse in the engine compartment box that is not installed from the factory?

i have an '07 Avalanche and this was why my Prodigy didn't work when it was first installed.
even the Chevy dealer had no idea that the fuse for the BC wires, was not installed at the factory.

[Iraqvet05]

kaydeejay wrote:

Iraqvet05 wrote:
............ Also makes sure the tow/haul button is pushed in when you test it.

I'm curious - since when did the tow/haul button have any effect on how an after-market brake controller works?

Nevermind...it doesn't. I was thinking of the 12V battery charge feed for the 7 pin connector that is only energized with the tow button on.

[kaydeejay]

Iraqvet05 wrote:
............ Also makes sure the tow/haul button is pushed in when you test it.

I'm curious - since when did the tow/haul button have any effect on how an after-market brake controller works?

[Iraqvet05]

Check the wiring at the controller harness to see if they wired it correctly. Here is how mine is wired (just checked it on mine):
factory harness color > Tekonsha harness color
blue > blue
red > black
yellow > white
green/yellow > red

Also, the engine compartment wire they should have hooked up is black/red and is all by itself...it should be pretty obvious they hooked it it to a stud under the fuse center lid. Here is the fuse info for a NBS Silverado...make sure they put one in.

[sbodi4d]

I have never had any problems with the standard brake lights not working. I am not sure what kind of testing they were doing. We were left walking around the dealership after closing looking for my truck. I left my cigs in the truck and needed one badly, so I started walking around looking for my truck, and found it with several people standing around it. When I walked up, I told them I needed my cigarettes, they started trying to explain why it wasn't ready yet. The guy that was trying to hook it up looked very frustrated, and proceeded to try to explain why they couldn't get it working. Basically telling me it was a factory wiring harness problem, and to take it to a dealer to get it looked at. This was Saturday night, and I don't know about you, but I don't know any dealerships that are opened on Sunday, much less the service department!
They are going to deliver my camper to me free of charge, but I need to get this issue taken care of before going camping. I looked on the Tekonsha website for help, but all they show are instructions for are 2007 classic body style. Nobody seems to have instructions for the 2007 new body style!!! Very frustrating!

[kaydeejay]

sbodi4d wrote:
Went to pick up my new Pup at the dealer yesterday, but they could not get the brake controller to work on my truck for some reason. I have a 2007 Chevy Silverado 1/2 ton new body style. I think they said they had power to the controller, but nothing back at the seven way plug. They told me there must be something wrong with the factory wiring harness, and to take it to a Chevy dealer to get it checked out. He said it would flicker on, but not stay on, so he thinks the controller is good, but I think it may be a bad controller. All I know right now is it is a Tekonsha controller. Not sure what model or anything, but they charged me $175.00 for the controller with installation.
Anybody had trouble hooking up a brake controller to a Chevy? The only thing on the truck that isn't factory is a Leer camper top that I had installed two or three years ago. The high mount brake light on the camper top doesn't work some times, but it works most of the time. The inside light for the camper top has never worked, but I was going to look at it sometime to see why. I don't think that has anything to do with the brake controller, but I have seen some strange electrical stuff before. Any input would be appreciated.

The red flag for me is the intermittent high brake light (CHMSL). That runs off the same feed from the brake switch as is used to drive the brake controller.
Are the regular brake lights working OK? The feed from them is split from the turn signal switch AFTER the CHMSL feed is taken off.
If the brake light feed is intermittent, so will the brake controller be.
A brake controller is not rocket science! The dealer tech should have been able to figure it out!

There are four wires:
- 12V power
- Ground
- signal from the brake switch
- output to the brakes

I would start by checking for the 12V power and then 12V signal from the brake switch. If this signal is intermittent, then so will the brakes be.
If these check out, check the ground and then continuity of the output wire back to the 7-pin at the back of the truck.
If this all checks out too, then, unless the controller is defective, you WILL get a brake signal at the 7-pin, but as someone else said, you do need some kind of a load back there for the controller to work.
Ideally, plug in the trailer and listen for the magnets clicking or humming, else wire a couple of stop lamp bulbs in parallel to ground to present a 3-4 amp load to the controller.

[j-d]

I don't know how the shop was doing the testing, but...
1. to test output at the truck (trailer not connected), a digital meter won't work. Takes a test lamp with some resistance. This is at least on some Tekonsha models.
2. Again, some Tekonsha models, was the preliminary leveling adjustment done and was the braking intensity turned UP?

[Iraqvet05]

I installed a P3 controller in my 07 (new body style) last year. Chevy runs the wiring for a brake controller but doesn't connect the powere feed wire to the terminal stud at the front of the fuse box in the engine compartment and doesn't supply the fuse needed to power that wire. Did the dealer add the fuse in the engine compartment box that is not installed from the factory? They should have also hooked up the power wire for the controller to one of the studs at the front of the same fuse box...that wire is unhooked and usually taped to another harness from the factory. Here is a 2006 examplebut should give you an idea of what to look for.