This has happened twice this week.

I'll be driving down the road and all of a sudden my radio will start flashing on and off for a minute or too.

One time the volt gauge on the dash cluster went all the way to 18.

It then went back to normal and everything seemed to be fine.

I was scarred it wasn't gonna start later but I haven't had any issues yet.

What should I look out for?

 

Bad voltage regulator. I think they are internal on our alternators, but haven't looked into it yet. But those are classic voltage regulator symptoms.

 

Voltage regulator is internal to the PCM unfortunately...... Check your fuses first, make sure something isn't shaking loose. Don't forget to have a look at the IOD fuse as well.

 

And check and clean ALL connections every where under the hood.

 

Alright guys Checked everything under the hood.

All checked out fine Except for two things.

1. The clamp on the negative battery post was extremely loose, I tightened it up, hopefully that's all it was.

2. The 20 AMP power outlet was blown, dont really know what the mines.

Not sure what the IOD fuse is?

The amp for the alternator is 80 but the box says its supposed to be 140 amp.

 

IOD = Ignition Off Draw. That supplies power for Radio, and PCM memory, and a couple other things. (dome lights as well I think)

I think ALL the trucks have that 140 amp fuse there..... I have the 136 amp alt, and I have the 140 amp fuse as well.

Loose battery terminal will definitely give you some odd behavior.

 

The actual fuse says its only an 80 amp though.

 

And the alt is 140 amp?

 

The lid says it is or supposed to be

 

Should be a sticker on the alt that will tell ya.