Trailer Lights on 2 Different Trailers Do Not Work When Connected to a 1999 Subaru Forester

Updated 08/11/2012 | Published 08/10/2012

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Hopkins Plug-In Simple Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

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Hook Probe Circuit Tester

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Question:

I have a wiring harness on my 99 Subaru Forester, accessible through the spare tire well. It recently quit working. Have two boat trailers and neither works, and cannot detect voltage coming out of the plug, so it seems the trailers are not getting juice. I cant find a fuse for this. Is it part of the wiring harness?

asked by: Jeff

Expert Reply:

It is possible that there is an in-line fuse somewhere back from the 4-Way end on your 1999 Subaru Forester. You will need to follow the wiring back as far as you can to determine if there is indeed a fuse. If you cannot find one, then consult the vehicle owner's manual for all of the fuses/relays in the vehicle associated with the wiring harness. Some vehicles have wiring fuses under the hood and inside the in-cab fuse panel.

If you have an aftermarket harness like # 33855 then you can test the wiring leading into the converter with a circuit tester like # PTW2993 if needed. If there is power going into the converter but not coming out to the 4-Way, then there is something wrong inside the converter and it will need to be replaced.

If it was a fuse that blew or a converter that went bad that may indicate that there was a short on the trailer that you will need to address, or this may keep happening. Check the wiring the the trailers for any nicks with exposed wiring touching bare metal, or exposed wires on the boat trailer that may be getting wet causing a short.

expert reply by: Michael H