View Full Version : Trailer Brakes Grabbing - Blinker Related - Sorry so long

01-01-2003, 05:28 PM
[eyecrazy]<br><br>I'm having a problem with the electric brakes on my car trailer. They work fine when stopping straight, so the problem only happens under a certain condition. This is a weird problem so will try to word it as clearly as possible.<br><br>The problem is that the brakes grab (harder than usual) and release very quickly several times when I use the truck blinkers (turn signals) AND have just taken my foot off the brake pedal; like when stopping at a stop sign then starting off again is when I notice the problem. As I turn the corner, and the blinker is still flashing, the trailer brakes will grab anywhere from 1 to 4 times until the blinker cancels out. It does not matter if I turn right or left. I can see the red lights on the brake controller spike as I go around the corner whenever the blinker flashes. Today I drove it around some and found that if I just put on the blinker (truck foot brake pedal not applied) then the trailer brakes would grab while the blinkers were activated. <br><br>If I do NOT use the blinkers at a corner and press the brakes, they release fine and I can go around the corner without the brakes grabbing again. So it definitely involves the blinkers.<br><br>Could the problem be in the brake controller? Today my Dad and I opened up the 7-pin connector on the trailer and found corrosion on the contacts inside. We cleaned it up, and there was no change. We both looked under the trailer and did not see any issues with the wiring. We did not take the brake drums off yet to look inside. I could probably borrow a brake controller from one of my friends, but I would like to hear what you guys think first. <br><br>My truck is a 2000 Dodge 2500 Non HO, 6-speed with a factory tow package. The trailer came with the brakes already wired from the manufacturer when I bought it. I am the only owner of the trailer, so nothing has been messed with. I used to tow this same trailer with the same brake controller and the same 7-pin plug with my 99 Dakota (factory tow package too) and did not have this problem. I would not think that there would be a difference in the 7-pin plug or the configuration of the wiring between the Dakota and the Ram. I am using the Chrysler supplied 7-pin that came in the glove box of the Dakota. The Dakota was an automatic and that is the vehicle I had when I bought this brake controller. The Ram I have now is a manual transmission. Anyone know if the difference in transmissions would cause this. I may or may not have the package for the brake controller since I have had it for over 2 years, so I am not sure if it was specifically made for an automatic transmission vehicle.<br><br>Also, the brake controller that I am using is probably not a high dollar one (I think it was $70), but it was the only one that I could find at the time. It has the factory style wiring pigtail, so it just plugs into the blue socket under the dash, so I have not spliced into any wires on the truck. <br><br>Sorry this is kind of long, but I wanted to cover all the bases.<br><br>Thanks for your help.<br><br>Mike<br><br>

01-01-2003, 05:44 PM
It sounds to me like a bad ground. When the ground is bad circuits will feed back through other circuits. In this case the brakes are grouped with the turn signals and if there is a bad ground the signals will feed back through the brake circuit. If you watch the lights you should see them doing some weird blinking, also a sign of a bad ground. This bad ground could be in the trailer wiring, in the plug for the trailer, the socket on the truck, or further upstream.<br><br>Chris

01-01-2003, 05:59 PM
I'm with Stamey; bad ground. I'd check all ground connections to the frames of both vehicles.

01-01-2003, 06:18 PM
I would say the trailer plug or the truck plug is wired wrong. The right turn and left turn lights on the truck are also the brake lights. The turn signal switch interupts power to the brake light when you put on the turn signals and makes that light into a blinker. That would explain why the brakes lock up since you are sending a full 12 volts to the trailer brakes every time the turn signal lights come on.<br>Find out which wire goes to the brakes on the trailer. Using a voltage tester on the corresponding wire on the truck, see if it blinks on and off when you put the turn signal on. If it blinks, that is the wrong wire. The real brake control wire should have a constant voltage (up to full battery voltage) depending on what controller and how hard you are applying the brakes.<br>A friend tried to pull my dump trailer home from his place one night and when he pulled the parking lights on, the brakes locked up. Classic case of wrong wiring. This is what it sounds like to me with the info you have supplied. Check and see that you have a good ground between the two vehicles as mentioned but it sounds like the wires are switched to me.<br><br>My trailers are wired with the standard 7 pin and start with 12 volts, right turn, brakes, ground, left turn, and parking lights going clockwise from the top master spline for lack of a better word.

01-01-2003, 07:02 PM
Thanks for the suggestions guys. I will look at the grounds and the way the wiring on 7-pin.<br><br>Mike

01-02-2003, 12:37 PM
I would recheck the controller wiring. Since we don't know the brand of controller that leaves us in the dark on one part of the equation. I would take a 12 volt tester and check the brake-light wire wire to the controller with the brake pedal depressed, it should be steady and bright, then recheck again with turn signal on. Is it still steady and clear. Next check the blue brake wire the same way. If it is not steady it is likely a controller problem.

01-02-2003, 07:16 PM
Here's a suggestion, drive like everyone else,don't use the directionals. [laugh] [laugh] ;D ;D

01-02-2003, 09:45 PM
If you are using the rv plug on the truck I have had alot of problems with it getting full of crud and shorting out inside its self. Somewhere in the plugs there is a short. I'm pretty sure that it is not your brake controler those will not run thru the turn signal. I couldn't figure it out on my 01 and ran a new plug and completely unhooked the factory and didn't have any more problems with it after that, put the plug in the bed no more mud and crud in it. When it rained the factory plug would turn on the brake box light.

01-03-2003, 05:47 AM
<br>Here's a suggestion, drive like everyone else,don't use the directionals. [laugh] [laugh] ;D ;D<br><br><br>Good one richard, why didn't I think of that one? [laugh]

06-09-2006, 10:02 PM
I had the same problem, several years ago.

NAPA has a little resistor-do-hingy-thingy that you rout the brake-light-to-brake-controller feed-wire through that will stop the controller from surging when the turn-signals are on.

I changed brake-controllers on my truck and it started doing exactly what you describe.

I installed the whatcha-ma-callit and no more problem.

06-10-2006, 05:53 AM
Hey bear killer that is some serious nasa tech talk there [laugh] I love it lmao