Clicking noise coming from tranny each time my turn signal clicks when in park

Hey guys,
I recently purchased a 2003 double cab with a 3.4 and auto trans
I noticed well driving home that my cruise control stops working each time I turn either one of my turn signals on, I also notice a slight down shift (jump around 250 rpms) when I turn my turn signal on. Then today I was trying to figure it out and put my turn signal on while my truck was in park and noticed a clicking noise coming from the tranny each time my blinker clicks. Any help would be much appreciated!

 

Sounds like an electrical ground issue. Start at the turn signal bulbs themselves and work your way back. With a new to you truck, you might find some "custom" wiring from the previous owner.

 

Do you have an aftermarket alarm and do you have trailer wiring.

 

Your hearing must be fantastic to hear a shift solenoid in the transmission.

It does sound like a ground feeding back through another circuit. The turn signals the transmission and cruise control do share some ground locations.

Charging system working like it should?

Physical damage to the harness or some left over custom wiring

Good luck wiring gremlins can be difficult.

 

Sounds like something is backfeeding the brake circuit either due to a short or bad ground, what your hearing is likely the shift interlock solenoid clicking.
I'd start with checking the rear bulbs, related grounds, and trailer converter harness if you have it.

If someone put LED bulbs in the rear that can cause this problem as well.

 

^^^ what he said.

Had this issue. Check your trailer harness, the turn signal can backfeed the brake light circuit if the harness is the wrong one, shorted, or wired incorrectly. The auto transmission uses the brake light circuit to signal unlocking the torque converter, so if stray current is ending up in the circuit, you have the issue you're describing. Turn on your turn signal and see if your brake lights are flashing in sync, it will prob be faint so look closely.