I need some help!

[caleb c.]

O. k. guys,my dad has a 03' 1 ton drw 4x4. And the problem is when you drive it the right turn signal comes on all by it self. We have had the front control module replaced 2 times with no help. The first time it did it it stayed on for about 50 miles. And they replaced the fcm and it started doing it again. And now we just replaced it again and it's still doing it. But it doesn't stay on,It will just come on once or twice and go off. It seems to happen every 20mins. or so. Any help would be great!Thanks

 

[PHeadings]

Sounds like a bad relay.

 

[sag2]

First of all the FCM only does (generally) what it is told to do. The turn signal switch is a resistor, and when the instrument cluster (CCN) sees a voltage change from the switch, it interprets it and busses a message to the FCM to turn on the right, left, or hazard lamps. You need to monitor the input to the cluster from the turn signal switch, and see if the voltage changes when the signal goes on by itself. If it does, bad switch, wiring, ground, voltage source. If no, possible bad cluster or cluster wiring, connectors, ground, power. Most likely not a bad FCM, as two have already been replaced with same result.

The dealer can monitor all this with the scan tool, but must be on the truck when it happens.

 

[bighammer]

I would guess a multifunction switch replacement might cure it.