instrument cluster stopped and not charging

[snowball]

Hi all,

I'm having trouble with my 90 burb. The instrument cluster went a couple of days ago, figured it was a ground issue, then the truck had a hard time starting.

Batt was at 11.9 jumped it and the voltage stayed low.

Replaced the alternator. same problem.

Checked the fuses and the gauge/idle fuse was bad. replaced it, turn the key to on, gauges worked for a second and popped the fuse again. Never started the truck.

With the fuse removed, the continuity sometimes shows a quick short on the fusible wire behind the alternator. It beeps for a split second if it tap directly on the wire. If I open the door it shows a short.

Anybody seen this before?

Anybody has a good diagram? it looks like that fusible link goes straight to the fuse box.

[Palf70Step]

I have not see your issue, but soulds to me something is shorted. Have you tested the battery? Even though they have good voltage, they may not hold it under load.

[special-K]

You'll probably have a fuse blown from a short in that circuit. You need to know what all is on that circuit, replace fuse, and track it down. Was anything acting funny prior to gauge loss? The truck won't charge when the amp gauge circuit is out. If fuse blows from a dead short, you'll need two people and a jumper for the fuse. Make one from two female connectors and a piece of fuseable link. Get set at each point you are checking and have your helper turn the key on only as long as you need to test circuit, then right back off. Was the idle working right, fast enough when needed and down enough when not? A wild guess would be a bad idle solenoid. It has to be either a short in the wiring or a bad part in the circuit. I would inspect wiring, then test at each component on the circuit and eliminate those pieces.

[snowball]

Thanks guys,

Palf, The alternator is not charging. With the engine running the voltage goes down. That gauge/idle fuse connects to the exciting wire on the alternator.

Special K, do you have a picture of the fusible link you're referring to?

What I was thinking of doing is disconnecting the cluster gauge, and testing the harness for ground. With the ground wire disconnected, then anything that leads to ground would be the culprit.

The only thing I would say was acting up is the temp sensor probably wasn't working right. She would idle low when I would start her warmed up.

Also, this beauty doesn't have a fast idle solenoid. it's a 90 burb 350 TBI.

Thoughts?

[snowball]

Quick question.

Anybody knows if the wire on the back of the alternator connects to the terminal block on the FW next to the booster

Thx