Brakes grab when crossing RR tracks, bumps

[garymacf]

Our 1974 Sovereign pulls fine except when we cross railroad tracks or any section of rough road. Then the trailer brakes cycle on and off, which makes for an interesting ride. I'm guessing we have some kind of short. Does anyone have a suggestion for where we should start the troubleshooting? Is there a frame ground location that might be a good starting point? Also, our trailer manual is missing (just under a stack of old National Geographics, I suspect. Does anyone have a source for wiring diagrams that can be downloaded?

Many thanks.

[overlander63]

Originally Posted by garymacf

Our 1974 Sovereign pulls fine except when we cross railroad tracks or any section of rough road. Then the trailer brakes cycle on and off, which makes for an interesting ride. I'm guessing we have some kind of short. Does anyone have a suggestion for where we should start the troubleshooting? Is there a frame ground location that might be a good starting point?
Many thanks.

Sounds like you have a 12v + wire that touches a brake power wire when you go over a bump. It is probably in the hitch plug area, that is where most of the powered wires are located. Look for chafed wires in the harness.
It may even be that when you go over a bump, the brake lights come on in the tow vehicle, because of a loose or misadjusted brakelight switch.
Good luck with it.

[TomW]

What makes you think the brakes are actuating?

I have noticed, through pulling a variety of trailers, that when the axle(s) clear whatever bump in the road presents itself, I feel a certain drag on my tow vehicle due to simply pulling the towed load up a small incline.

FWIW, I know on my JetSki trailer that part of the drag is the tire hitting the improperly mounted fender . Are your axles in good shape?

Tom

[greg176]

Could this be caused by an inertial brake controller?

[overlander63]

Originally Posted by greg176

Could this be caused by an inertial brake controller?

It could, if the brake lights came on. The controller uses the brakelight signal to activate the trailer brakes.

[garymacf]

I believe the brakes are definitely cycling...I don't think it's bad axles or something hitting the fenders. But for starters I'll have someone follow me while I cross some RR tracks near the house and see if the brake lights are coming on or not. Good suggestion. Thanks.

Gary