P0620 Generator circuit fault.

Jake · Aug 19, 2014

What are yall finding on this? The truck is still charging.

Dual alternators.

Batteries less than a year old.

I am going to go check the fusible links, the battery light has been intermittent which makes me think brushes in one of the alternators. I have never seen this code on the truck before. It started shortly after there was a fault on the trailer clearance lights.

Thanks guys!

Jake · Aug 19, 2014

oh yeah battery light is on for like a minute after startup.

suprdzlduty · Aug 19, 2014

I have seen that quite a bit on dual alt trucks...probably you're right about the alternators. The PCM randomly picks which alternator to use each start up, I would convert it back to one alt. all you need is the jumper plug that goes in the secondary alternator harness on pass side fender well. That way you only have one to deal with and replace.