Anyone know instrument gauge problems 88 Pickup?

[33Chev]

Just picked up a 1988 Chevy 2wd 1/2 ton pickup with 305/5sp. The kid that had it let it go and I'm going through it.

The instrument panel trouble light "Check Gauges" is on. I also noticed that the temp gauge is at 3/4 with the key off...but drops to zero when started. Same similar thing with the oil gauge..the gauge bottoms out when started and running.

It has those type of gauges with white lines across the front and the back portion (white) scrolls behind the lines (like the land of the rising sun)

Any hints before I dig into it?

thanks

[broughy84]

The temperature gauge stays exactly where it was when the truck was running last, or it's supposed to, untill the key is on. When you turn it on it should drop (if the engine is cold) and while you are cranking it should peg all the way to hot. Oil pressure stay the same with the key off too, until it is started, but it doesn't peg like the other one does. I would first make sure that you have oil pressure with a manual gauge under the hood and then I would test the sending unit. Gauges are tricky to change in these, but you can usually find them a dime a dozen on ebay. Most of the time it is cheaper to buy the whole cluster (speedo, and all) than just the gauge, and then you will have more gauges if your others fail.

[33Chev]

Matt:

Located a copy of the wiring schematic and deteremined the problem to be in the oil pressure side wiring. The top oil switch (for the ECM and fuel pump) obviosuly wasn't the problem. I then checked the oil pressure sending unit near the 305 oil filter...and bamb....the circuit was closed (bad sending unit). Installed a new one from Autozone at $20 and the lights went off and the oil pressure gauge is working again. The entire instrument cluster is working fine.

I would have never thought a sending unit would affect the intrument panel...

Ed

Buffalo, NY