Brake Controller Light Flashes when Trailer is Connected to a 1989 Chevy C/K 2500 Pickup Truck
Question:
I have an 89 chevy 2500 had a draw tite 5504 installed today and without trailer hooked up light on unit seems to function normally bright on high and dim on low but when I use manual activation no light and a very loud buzzing unless my foot on brake first. I put trailer on and it will only function on high but the light slowly flashes on and off with brakes applied and it turns trailer brakes on and off at the same time at about 1 sec intervals makes for a very strange feeling. if I turn down even a little bit I only get extreamly dim light and little to no trailer brakes please help
asked by: Jesse B
Expert Reply:
It sounds like either the white ground wire is not properly connected or is not connected to the best ground location or there is a short to the blue wire.
First, make sure you have the white ground wire attached to the negative battery terminal. This is the best ground location for a brake controller. No other ground locations will really work as well.
To test the # 5504 controller, in the truck cab you will need to sever the blue wire several inches from the back of the controller. Then use a circuit tester such as # PTW2992 to test the end of he blue wire coming out of the controller. It should only have power when you apply the manual override or brake pedal. If it shows power at idle then there is something wrong with the controller and it will need to be replaced.
If it tests fine then reconnect the blue wire. Then move on to the truck side trailer connector. Many times, dirt or corrosion can cause a short in a trailer connector. Make sure the truck and the trailer side connectors are clean and free of corrosion inside and out.
You can test the brake output pin and it should only show power with the manual override. If it shows power any other time then there is a short somewhere between the connector and the brake controller you will need to track down.
If the truck side checks out fine then it could be the wiring to the brake magnets or the magnets themselves. Inspect the power wires to the magnets and look for pinched, frayed, or damaged wires and fix as needed. Make sure the ground wires are attached to clean and corrosion free bare metal surfaces.
You can visually inspect the magnets and if you can see the copper windings coming through the magnets will need to be replaced. To further test the magnets you can follow the help article I have linked. I have also included some help articles on testing and troubleshooting brake controllers for you.
