Trailer Brakes Lock Up w/Headlights On

[Crankshaft]

I have read other threads about this problem but they didn't offer a solution. My tv, a GMC Sierra with the same brake controller has towed two other tt without a problem. Now I have a Windjammer purchased last year and haven't towed at night until recently. When the headlights are on the electric brakes lock up. I changed brake controllers to a Prodigy 2 just for grins but with the same results. I have called customer service without satisfaction. I know it is a wiring problem within the trailer but where do I start. Has anyone had AND solved this problem? Any help would be greatly appreciated.

[TURBS]

Here's how trailer should be wired.

[bakken]

You say that 'when the headlights' are on, but does it also happen with just the clearance lights on as well? If so, it sounds like they cross-wired the camper lights with the brake system. If so, that should be an easy fix.

[wmtire]

It could be in your TV wiring harness, as GM changed them. Here is where I discussed it with another member a few years back.

http://www.forestriverforums.com/for...-on-13664.html

[Crankshaft]

I am familiar with the harness wiring schematic. The trailer end is molded together and the harness, of course, runs under (into) the trailer. I'm not sure where to go from there. I haven't tried just the "parking" lights...just the headlights when they come on in the Auto mode. I suppose it could be either the parking light or the headlight wire crossing somewhere with the brake wire.

Thanks for the reply anyway.

[wmtire]

Originally Posted by WindJammer2012

I am familiar with the harness wiring schematic. The trailer end is molded together and the harness, of course, runs under (into) the trailer. I'm not sure where to go from there. I haven't tried just the "parking" lights...just the headlights when they come on in the Auto mode. I suppose it could be either the parking light or the headlight wire crossing somewhere with the brake wire.

Thanks for the reply anyway.

It's the wiring harness inside your vehicle under the dash going to the brake controller. It is explained in technical service bulletin from GM in the link I provided, and your vehicle year is listed.

Trailer Brakes Applied When Headlights/Park Lamps Are On, Brake Controller Illumination (Modify Brake Controller Wiring Harness) #02-05-22-004C - (Apr 5, 2005)

1999-2005 Chevrolet Silverado

2000-2005 Chevrolet Suburban, Tahoe

2002-2005 Chevrolet Avalanche

1999-2005 GMC Sierra

2000-2005 GMC Yukon, Yukon XL

2003-2005 HUMMER H2

This bulletin is being revised to add additional model years. Please discard Corporate Bulletin Number 02-05-22-004B (Section 05 -- Brakes).

Condition
Some customers may comment that when the headlamps or park lamps are on, the brakes on the trailer are always applied, or that the back lighting for the trailer brake controller only illuminates when the brakes are applied.

Cause
The cause of this condition may be due to wiring changes within the vehicle electrical system for the 2003 model year.

Correction




Inspect the brake controller wiring harness jumper that is plugged into the vehicle relay block-body. The relay block-body is located under the left side of the instrument panel near the left kick panel, behind a plastic cover.

The 1999 though early 2003 wiring harness jumper that plugs into the relay block will have a reddish/brown 6-way connector and a tag with the last four digits of the wiring harness part number. Second design 2003-05 may have a white plastic connector with part number 5418 as well.

• The 1999 jumper is/was P/N 12171982 with a pink/purple tag identifier of 1982. This number has been superseded to 15366255, with a pink/purple tag identifier of 6255.

• The 2000 jumper harness is P/N 15366255. The pink/purple tag identifier is 6255.

• The 2001-2002 jumper is P/N 15086884. The orange tag identifier is 6884.

• The 2003-05 jumper is P/N 15085418. The orange tag identifier is 5418.

When transferring the brake controller with the wiring jumper attached from a 2001-2002 vehicle to a 2003-05 vehicle, a change to the jumper harness connector must be performed.





The following information is for the 1999-2002 wiring harnesses.

Pin
Wire Color
Circuit Number
Function

A
LT BLUE
1620
Stop lamps

B
RED
142
Brake controller 12 volt source

C
DK BLUE
47
Brake Controller output (Trailer Brakes)

D
BROWN
2409
Brake controller illumination

E
--
--
--

F
BLACK
1850
Ground


The following information is for the 2003-05 wiring harness.

Pin
Wire Color
Circuit Number
Function

A
BROWN
2409
Brake controller illumination

B
RED
242
Brake controller 12 volt source

C
DK BLUE
47
Brake Controller output (Trailer Brakes)

D
LT BLUE
1620
Stop Lamps

E
--
--
--

F
BLACK
1850
Ground


To modify a 12171982, 15366255 or 15086884 harness for use in a 2003-05 vehicle, switch the wires in cavities "A" and "D".

To modify a 15085418 harness for use in a 1999-2002 vehicle (see model list at the front of this bulletin for applicable models), switch the wires in cavities "A" and "D".

Warranty Information
When the correct wiring harness P/N is matched to the specific model year of the vehicle, everything works properly. Therefore, conversion of an incorrect wiring jumper to match the vehicle would not be considered a warrantable repair.



GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

[Crankshaft]

wmtire,

That is one that I read earler and could'nt reply to because of the thread's age.

The 2004 tv worked correctly with a 2000 Arctic Fox but not the 2012 Windjammer. If I turn on the park lights the clearance lights work on the tt and also stay lit with the headlights on. So if either one of the wires were crossed to the brake wire then the clearance lights wouldn't work. The brakes work when I use the maual mode on the brake control and that wouldn't happen if the wries were crossed.

[TURBS]

Originally Posted by WindJammer2012

wmtire,

That is one that I read earler and could'nt reply to because of the thread's age.

The 2004 tv worked correctly with a 2000 Arctic Fox but not the 2012 Windjammer. If I turn on the park lights the clearance lights work on the tt and also stay lit with the headlights on. So if either one of the wires were crossed to the brake wire then the clearance lights wouldn't work. The brakes work when I use the maual mode on the brake control and that wouldn't happen if the wries were crossed.

Fyi you can reply to an old thread you just have to accept the box sayin you know its an old post.

[Crankshaft]

Thanks for the FYI Turbo. I did not know that.

[wmtire]

Originally Posted by WindJammer2012

wmtire,



The 2004 tv worked correctly with a 2000 Arctic Fox but not the 2012 Windjammer. If I turn on the park lights the clearance lights work on the tt and also stay lit with the headlights on. So if either one of the wires were crossed to the brake wire then the clearance lights wouldn't work. The brakes work when I use the maual mode on the brake control and that wouldn't happen if the wries were crossed.

The windjammer trailer, is this the first time you have used it with this vehicle? Has it ever worked correct on another vehicle to your knowledge?

[TURBS]

Underneath your jammer there will be a household looking junction box.
There should be an access cover in the underbelly.
Pull that cover off and see what the blue wire is hooked to.

Turbs

[Crankshaft]

I bought the trailer "used" last August. Only nine months old since being bought by the original owners in Delaware so don't know if they had problems. Usd the trailer last September for three weeks but didn't have a need to drive at night or any other time with the headlights in use. Last month we used it for another three weeks and had to use the lights twice. Both times the brakes locked up. No one else in the family has a tv to test it that way.

My whole quest in this forum is to see if anyone else has had this problem and how they fixed it.

[Crankshaft]

I will look into the junction box. Maybe a short or miss wired but if it miss wired then either the lights or brakes wouldn't work when they should. This is a problem of the brakes working when they shouldn't. They brakes work ith either the brake pedal or manual. The lights work when they are turned on. The problem is that the brakes work when the lights are turned on. If the brake wire is connected to the lights then the lights would come on when the brakes are applied and the lights wouldn't come on with the light switch and the and the brakes wouldn't work with the controller. There isn't any warning of wiring fault on the Prodigy 2 when connecting to the trailer. It's like the trailer brake wire is connected to both the tv brake wire AND the running light wire.

[TURBS]

jammer , one would think thats true but I don't think it can happen.
I would check that box and check back .

[Crankshaft]

When we have decent weather here in Denver (tomorrow?) I will side underneath the trailer and check it out.

Thanks for everyone's input...will advise after inspection.

[wmtire]

This guy in the link below sounds like he had your same problem. He stated he had a trailer that worked correct, then got another trailer that locked up the brakes when he turned his headlights on.

Several people offered suggestions, and you might check those out to see if you may have similar. The OP fixed his problem by changing the GM wiring harness to the brake controller under his dash.....which I believe may still be your problem. I also think your 2000 year model trailer may have been wired different from your 2012 one too.....thus the reason your TV and Trailer worked.

Here is the link:

Truck lights trigger trailer brakes!!!!!!!!! - Diesel Place : Chevrolet and GMC Diesel Truck Forums

Here is another forum with same problem and fix. This one gives diagrams how to swap pin locations:

http://www.rv.net/forum/index.cfm/fu...print/true.cfm

This pdf explains the trailer brake jumper harness for the brake controller. A-22 is what you really want to read.

http://www.gmupfitter.com/publicat/2...lectric_CK.pdf

[Crankshaft]

wmtire,
I can hardly wait until tomorrow so I can check the wiring under the dash of the truck. Your links provided a wealth of info which I was unaware...like GM changing the configuation of the wires. If this is the solution to my problems one question will still remain. Why did everything work correctly with my old trailer?? I thought there was a standardization for all of this between manufacturer's...silly me! Thanks for your detective work! I will also retain that forum for future references on my truck. I love these forum boards!!

[wmtire]

One of the guys in the forum links I provided, stated he called Prodigy and they gave him a two minute fix to the problem. You also might want to give them a call and see what they say, since you just bought a P2 brake controller. I would talk to them first, and see what their take on it is.

Here is a quote from it:

It's a problem because Chevy kept jacking around with pin locations and most dealers are stocking the OLD Prodigy harness...which leaves you with trailer brakes activating when the headlights come on!

Somewhere on here I posted on this very same issue with my 2005 Silverado and P3 controller. I called Prodigy and they sent a 2 minute fix.

[Crankshaft]

I just came in from dealing with the problem. Oh, BTW Forest River Tech Service had never heard of this problem. No help there!
Using a digital VOM, I checked the voltage at the truck end. I had 4.2 volts at the eletric brake terminal with the lights on. When I bought the new Prodigy 2, I went ahead and purchased the harness for my truck. I did not use the new harness when I installed the controller because it was the same vendor (Tekonsha) just an older model. Today I swapped out the harnesses noting that the wiring configuration was different. Now, I have .12 volts at the bumper. I also have the same voltage at all of the terminal except the 12v terminal of course. This should not be enough voltage to actuate the brakes. I didn't have time to connect to the trailer to complete the testing.

[garbonz]

GM's had two different wiring schematic back then. I ran into the same thing with my 2007 wired wrong at camping world and then rewired at the dealer when I picked up the trailer.