Hopkins Trailer Brake Controller Shows 4.5 Volts All the Time on a 1992 Chevy C/K1500
Question:
Wired correctly. 1992 chevy 1500. Blue brake wire has 4.5 volts all the time. unhooked wire to rear. no change. voltage jumps to 6volts briefly when brakes are applied then back to 4.5 with blue wire to rear disconnected. test light does not light when brake isnt pressed although test light shows 4.5 volts. Very odd? This is a new install. does the unit detect ground feedback through the blue wire?
asked by: Steve T
Expert Reply:
Brake controllers do send back minimum voltage to detect a trailer but not 4.5 volts constantly. It sounds like there is a short somewhere or perhaps the red wire is not connected to the correct brake switch wire. That is where I would start. Use your tester to test the wire that the brake controller red wire is attached to. It should only have power when the brake pedal is pressed and not also when the headlights or turn signals are on.
If that is correct then to test the controller you will need to sever the blue wire a few inches from the back of the controller. Then use your tester to test the end coming from the brake controller. It should only show power when the manual override is applied. If it shows power at any other time that indicates a problem inside the brake controller and it will need to be replaced.
If the controller works fine when you do this test then reconnect the blue wire. The issue is likely a short somewhere between the controller and the 7-Way. But before checking that make sure that the white wire is attached to the negative battery terminal.
Trace the brake output wire from the back of the 7-Way forward on the vehicle as best as you can. You are looking for any breaks in the wire or loose connections. Fix as needed. Make sure that none of the wires in the back of the 7-Way are touching. And make sure the 7-Way pins are clean and free of corrosion. I have included a link to a help article on brake controllers for you.
