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'96 Chevy K1500
Open dual-axle trailer - brakes on both axles
Draw-Tite Activator II brake controller
Works fine in the driveway, and early in a tow. After towing a while, the brake controller overloads when activated while moving, but not while stopped - strange.
Is this likely a defective controller, bad wiring, or something in the trailer brakes? How do I track it down?
Thanks,
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Marty Doane
ITS RX-7 #13
CenDiv WMR
Marty,
I had a similar problem and it took me quite a while to find it.
Turned out the wires to the brake had chaffed where they pass thru the axle tube to go from one side to the other. The brakes would work fine under static test, but would short out after driving for some distance, when the wires would bounce just right and touch the frame.
I wound up tracing and inspecting every inch of the wiring. When I got to the suspicious area, I had a helper apply the brakes while I wiggled the wires.
You can test your controller by hooking up a 12V test lamp to the two pins at your connector. I use a brake lamp bulb since it puts a bit more load compared to a tail light bulb. If your controller is working correctly, the bulb will vary in brightness from dim to full as you adjust your controller from low to high setting.
If it fails that test, you have a bad controller. If it passes, your problem is on your trailer.
Hook up an ohmmeter to the trailer connector, across the two pins for the brake wires. You should measure some low resistance like 5-10 ohms (it will depend on the impedence of your particular brand of trailer brake). If you measure 0 to 1 ohms, you have a short somewhere. Start wiggling the wires while you watch the meter. The brake wires will tyically be a seperate two-conductor cable with heavier gauge wiring, compared to the trailer light cable, so they should be easy to trace. If they pass thru the axle like mine did, I would check that area first. A little tape, add a grommet, and you'll be set.
I know that this is harder for some than others, but if you have a friend with another trailer or truck you could try another trailer with your truck and/or another truck with your trailer and see which component the problem follows.
dick
About 6-7 years ago, I swapped my old 1 ton gas van for a 1 ton diesel van, and equipped it with a Draw-Tite electronic controller. The paperwork with the controller said that it could handle up 3 axles of brakes. I figured it was a good controller, and a nice upgrade. Har.
Within 3 months, I had heaved the controller into the heap of useless junk in the back of my shop, and gone back to 'old reliable' - a Tekonsha. The Draw-Tite would contantly overload...which means that it would just QUIT WORKING. The LED display window would flash etc. etc. etc. It just seemed that it couldn't handle the current required to keep 4 brakes engaged.
It did this with both my open trailer (2 axles w/brakes) and my 24' enclosed (2 axles w/brakes).
There is nothing as 'pant-filling' an experience as having your brake controller 'check-out' during a hard, unexpected stop.