Troubleshooting Stop/Turn Signal of a Optronics Light part # ST45RB on a Trailer

Published 04/02/2014

Products Featured in This Question

Optronics Trailer Tail Light - Stop, Turn, Tail - Submersible - Incandescent - Round - Red Lens

(2545)

$5.06

Hook Probe Circuit Tester

(60)

$12.27

Question:

Is it normal for a turn signal to stop working and yet the tail light and brake light still work in the ST45RB. My trailer is about 8 years old and I have never changed one of the tail lights before. The brake light may not be working in that bulb as well, but it is on dim for a tail light. It just doesnt blink on turn. Since this is a single bulb, I wondered if it could be the Light or if it is in my wiring.

asked by: Jeff H

Helpful Expert Reply:

It sounds like the problem is in the wiring. If your light is a dual intensity light and both intensities are working with the running lights and brighter with the brake lights then the problem lies in the turn signal circuit most likely on your vehicle. You might test the trailer connector on your tow vehicle with a circuit tester like our part # PTW2993 like the video I attached shows to determine if the wiring of your vehicle is good.

If the problem is in the vehicle wiring you will need to trace the wiring back up to where it installs on the vehicle looking for and fixing any obvious signs of shorts like cut or exposed wire.

If only the dimmer intensity is working then the problem is most likely the stop/turn circuit of that assembly. Or it could be a weak ground. Check the ground of the assembly and make sure it is attached to a clean metal surface. The extra amperage draw of the brighter intensity might be more than the ground can support and that is why its not illuminating. Also check the trailer connectors for corrosion and clean as necessary.

I attached an FAQ article on trailer wiring for you to check out as well.

expert reply by: Jameson C