I have a '99 Ford Ranger XLT and the left rear turn signal lights up when I depress the brakes. Also when the head/tail lights are on, and I turn on the turn signal, both rear turn signals light up, and all three tail/brake lights flash. They take turns coming on. (the tail lights and the turn signals). They dont all light up at one time. Also, when the brake is depressed and the turn signal is on, the turn signal flashes more rapidly...What is going on?

 

I had something similar happen to my 94. I'd purchase/replace with a new wiring harness for the hitch. A faulty harness can cause a miriad of problems including affecting the cruise control. You can get one at any Rural King, Tractor Supply, etc. for around $25.

Good luck!

 

Yup, I agree. Sounds like a problem with your trailer plug harness. Look under the bumper near the left taillight. There should be a connection in the truck wiring harness with the trailer adapter plugged in the middle. Unplug both ends of the harness from the trailer module and then reconnect the truck harness without the trailer adapter.

 

I appreciate your help...I looked down there and it turned out to be the harness itself...the receiving end of it was burned and there was a short between the brake lights and the turn signal. I have to replace the harness.

Thanks for the tip