Troubleshooting a 7-Way Vehicle Connector That is Showing Voltage but Not Amperage

Question:

My trucks 7 way plug is showing 12 volts , but no amps . So my brakes are not working . What could cause this ? How do I repair it ?

asked by: Terry C

Expert Reply:

You can have voltage without current. It just means that the circuit is open. The sockets themselves do not have an amperage rating, so the amps drawn would be dependent on what is being used. In your case, the brakes. To get a proper amperage reading, you would need to have the trailer plugged in with the brakes activated, you can then test the trailer side wiring behind the connector to get an amperage reading.

The other thing could be how you are testing the brakes. If you have a proportional brake controller like the Tekonsha Prodigy P2 Trailer Brake Controller # 90885 you would either have to use the manual override or be moving when testing the brakes. The movement would be required because the proportional controller needs to sense movement to activate the brakes.

If you have been doing all of that, I would take a look at the trailer brake wiring itself.

expert reply by: Scott S