I just bought a 97 Expedition to use to tow my boat around. The truck has 165k miles and runs great. The only thing I notice wrong with it are the temp, oil pressure and voltage gauges are all maxed out. They seem to work properly when I start the engine then after a minute or two they all max out. I checked the voltage at the battery and it is about 14 volts and there are no other warning lights or indicators of anything wrong. Any ideas why all 3 would go crazy?

 

This can have a few causes. Usually, I'd say there could conceivably have a wiring problem (are they hooked up? But that wouldn't affect the voltage reading). If you're not in CEL territory from a possible AC waveform introduced into the system by a mostly-properly charging alternator (it would probably miss intermitanly and run rough if it did, and randomly), then I'd say the safest bet is the internal (to the cluster) cluster voltage regulator. That's my bet if everything else checks out. It fits the description where it's fine for the first few minuets, then goes south.

 

Thanks Greasemark, I think you hit it on the head. I had the battery and alternator tested last night and all were functioning properly. Now for the million-dollar question: where is the ICVR and how do I get to it? I'm finding it quite elusive on the web.