Troubleshooting Trailer Lights not Working With 2010 Toyota RAV4

Updated 05/21/2018 | Published 05/19/2018

Products Featured in This Question

Hook Probe Circuit Tester

(72)

$13.14

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

(301)

$66.11

Question:

Installed Curt 56165 on 2010 Toyota RAV4. All vehicle lights function normally brake,turn,4way. Trailer plug has: LH turn- green cycles, RH turn- 0 v. @ green, getting constant 13.40 v. @ yellow. This is the 2nd Curt 56165 to have same issues, both purchased @ etrailer. The hitch is great but w/o trailer lights very little use. This is my second message, got no response from the first. Thank you.

asked by: Jerry S

Expert Reply:

With over 13 volts there is likely a short somewhere, but in order to determine the specific problem you'll first need to use a circuit tester such as # PTW2993 to test the connector on your RAV4 after disconnecting it from your trailer. Check the wiring going into your harness from your taillights to see if those wires are carrying the correct signals, if not then the issue is with the vehicle wiring. If the signals going to your harness are okay, you'll need to test the signals coming out of the harness, and if they are correct then your issue is likely going to be with the trailer side wiring.

Another important issue you will want to take a look at are the ground connections, as they can be the cause of numerous lighting problems. You'll want to make sure your grounds are securely attached to bare metal surfaces free of any paint, dirt or corrosion of any kind. Also check your wiring thoroughly to ensure there are none that are crimped, broken or otherwise damaged. This may be the cause of the short that could be happening and resulting in you getting that many volts. It is not the Curt harness that is causing the issue, however, it is the current wiring.

I've added links to a pair of help articles on trailer wiring that you may also find useful.

expert reply by: Kyle S