2000 Toyota Sienna With Low Voltage At 4 Pole Plug

Question:

It will not work on my utility trailer because the voltage so low at the plug! Why?

asked by: William M

Helpful Expert Reply:

The Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector Item # C55418 on your 2000 Toyota Sienna with low voltage at the plug is most likely a ground issue. Follow the ground wire from the converter box to where it is grounded to the vehicle. If the self tapper was used, make sure the self tapper did not back out a little. Sometimes if the metal is not thick, the self tapper may not get tight enough and the ring terminal will be able to move. If this is the case re-locate the self tapper and ground wire and test again. I like to try to find a piece of metal that is doubled up or a factory ground screw.

You can also do a process of elimination. Unplug the wiring harness from the connectors. Test the vehicle light functions at the connector and see if you are still getting a low voltage reading. If you are, then it's the vehicle side. If not then you can eliminate the vehicle as the cause and you will know it is the wiring harness.

expert reply by: Shane H