Posted by Mike on November 10, 19100 at 12:02:55:
In Reply to: Funky Dash Readings posted by Joe A on November 10, 19100 at 08:41:14:
: My 92 K2500 dash board has a mind of its own. The Oil pressure gauge is pinned on startup and jumps around after its warmed up. The temp guage drifts from 200 to 220 much too quickly to be accurate and the voltmeter reads 12V every once in a while even the I have measured the battery to be dead on at 14.2V (and I have new Amptech alternator), Any Ideas???
Here's how to tell. Park it facing a wall. Start it up. When the gauges go nuts, check for headlight flicker. If they do, then it's one of the four main battery connections, pos/neg and engine ground or starter. You may also have a separate pos wire going from the battery to the "convenience center" (fancy relay and fuse box). So you may have 6 places to check.
If the don't flicker, then it's the ground strap in the instrument cluster. All the gauges share a common ground. A general rule is that if one gauge is flaky, it's probably the sending unit. If more than one is flaky, it's probably the shared ground.