I have an '08 Alpha H3. I have the passenger rear turn signal stuck on all the time. The reverse lights work fine and the middle brake light is fully operational. I have blown the 20A turn signal fuse 7 times trying to troubleshoot. I've changed all 4 light bulbs in the back and they are all fine. When I first recognized the problem I found some water in the bottom of the passenger lens cover. My suspicion was that it caused my problem. Now, the drivers side signal will work until I touch the break pedal and then it blows the fuse. With the fuse blown, both make the rapid blinking sound.

I've looked through the forums and saw the advice about the tow pkg wires. There is no corrosion or wear showing that I can find. I've also heard people say they've had to replace the BCM. I took it to a local repair shop and they told me it was my "Turn Signal Switch". I see them online for about $150. A trusted mechanic told me that "usually a turn signal switch won't cause a fuse to blow". He's on vacation or I would trust him to look it over. I hate to buy the Turn signal switch online and that not be the problem. My bumper to bumper warranty ran out about 6 months ago, so this is on my dime. The repair shop told me it was going to cost $580 with parts and labor. I told them to hold off and I was going to do some checking. Does the switch make sense to you? Is it something that I can do myself? I don't want to cause other problems with my security system or other light mechanisms by trying to save a few hundred dollars. Any advice would be appreciated.

 

Howdy Dean, welcome.

The trailer hitch wiring deal you touched upon is not completely correct. Where my vehicle harness shorted out against the bottom of the chassis under the rear door was not part of the trailer wiring, rather it was close to where the rear license plate light wire shoots off. You could try looking at that?

Also try spraying electrical contact cleaner in the trailer plug receptacle, over time dirt and crud can bridge between pins (especially when wet) and cause a short out..... like when power is supplied to the brake pin???

Easy stuff first. Best of luck. Please report back what you find, and for sure when you get it ironed out.