08 Kenworth. All lights work on truck and trailer except the signal lights. The trailer signal bulbs are fine as they are also used for the brakes. What to check?
When I drove for Marten my turn signals stopped working. Dispatch told me to get a replacement blinker relay. I did a little online research and found the location and number. I r&r the part and all was smooth sailing. Instead of searching through a forum, Google search it. That way you may find your answer in a forum you may not be registered to.
Check the fuse first. If the fuse is ok, then it could be the flasher “relay” which is usually behind or under the dash. Looks like a small square box or round with 2 prongs(connectors) hooked to it. If it is the flasher relay, replace it with a heavy duty one.
Always check fuses first. The 07 I used to drive would pop them every time it rained. The problem was in the trailer.
You need to locate the flasher relay. It's the same think that makes the clicking sound when the blinker is on . It may just need to be pushed back in all the way or could be failing. If you can find it it's a easy as unplug and plug in a new one. Can be found at any parts store and even most truck stops
