Turn Signal on 2004 Toyota Sienna Hyperflashes with Brake Pedal with Wiring Harness 118304 Installed

Question:

After installing kit 118304 on my 04 Toyota Sienna, the left turn signal flashes fast if the brake is pushed. This was before hooking up the trailer. Also when the brake is pushed the left turn signal indicator on the dash comes on sometimes. All the trailer lights seem to work fine. After unhooking the kit the turn signal works normally. Any idea what might be causing this? Thanks

asked by: Greg J

Expert Reply:

First let's make sure that everything is hooked up properly. The red and green wires on harness # 118304 will go to the passenger side and the yellow and brown go to the driver side. If those were swapped it could cause some issues. Also make sure that the white ground wire is attached to a bare metal surface. Moving the ground could help. Ground problems can cause all sorts of weird things to happen.

To determine if the converter box is bad, you will need a circuit tester, # PTW2993, if you do not already have one. Use the tester to test the wires going into and coming out of the converter.

If the signals are correct going in but not coming out to the 4-Way, then there is a problem with the converter, and it will need to be replaced. If the signals are not correct going in then that indicates an issue on the vehicle tail light wiring that will have to be tracked down, but I do not think this is the problem.

I have included some links that will help you troubleshoot.

expert reply by: Michael H