Twitchy instruments

[319cssb]

The gauges ( some of them) twitch at times. Is there a known cause for it?

 

[jkcondrey]

Maybe a fluctuation when alternator is cycling? I've seen that on some other vehicles.

 

[porkysplace]

Bad grounds.

 

[319cssb]

Bad grounds.

got any place to look for bad grounds? behind the instrument panel? Fuse panel? Or alternator?
What you said is very generic.

 

[Suprman]

Depends on the year of the truck and what engine it has. I would start with battery terminals and the elbow bolts. Main ground at starter. Power wires coming into the cab. Alternator cabling. Make sure the alternator isnt going into protect for some reason or loosing excite power momentarily. There are grounds all over the truck. With age things loosen up and corrode. The previous owner sold it because they didnt want to deal with it anymore. The TM isnt much use for intermittent electrical issues unfortunately.
Will

 

[319cssb]

This truck is a 1996 with 3116 engine.
I'll start at the battery and take off terminals and clean them. Then put on some Dielectric grease.

I agree with what you said about the TM's I couldn't find anything useful about intermittent stuff.

 

[porkysplace]

This truck is a 1996 with 3116 engine.
I'll start at the battery and take off terminals and clean them. Then put on some Dielectric grease.

I agree with what you said about the TM's I couldn't find anything useful about intermittent stuff.

I would also disconnect the batteries when cleaning any grounds or doing anything with the electric system for that matter.

 

[319cssb]

Trying to find a ground distribution chart. Can anyone point me to the right spot in the TM?

 

[Ronmar]

Trying to find a ground distribution chart. Can anyone point me to the right spot in the TM?

Havnt really come across a definitive one. On sheet 15 of 34 of the electrical schematic you will find TB2 which is the ground tie point for most of the cab wiring. It ties to the ground lug in the power panel which ties down to the cab-chassis ground point by the passenger side cab mount/pivot.

Most all of the other grounds are large cables, alt-chassis, battery to chassis, starter to shunt ect.

 

[319cssb]

I am not sure if going through the ground connectios will help.
But it sure will help something. I am cleaning the connection, add dimension by roughing th surface and then coat with dielectric grease.

I looked at the oil gauge a bit closer and it at first reads a steady readout and then starts to tremble and twitch.