My battery went dead on my '86 coupe. After jump starting it, I noticed the digial volt readout was 9.9v, the coolant temp was 172deg, the oil pressure was 72lbs, and the oil temp was 125 degrees. I charged the battery to 13.2v (using a battery charger), the car starts and runs great, but these digital readouts haven't changed. All the other readouts seem to be normal---tach, speedometer and gas gauge all work, as well as the average & instantaneous mileage. Also, when I change the readout from volts to coolant temperature, the readout changes then immediately goes back to 9.9v.

any ideas what might be causing the problem??

thanx

 

Got a multimeter?

Check the alterntor output(with moto running). Put the positive on the alternator output terminal marked 'field', and ground it. You should get 12 - 16 volts.

Check the positive clamp on the battery the same way. Should get near the same result. Do the same with the battery post. If you got side post, you'll have to just unscrew each post, check for corrosion, check battery voltage, and re-connect.

After that, follow the wire lead to the guage cluster, to find the voltage drain. A tough task, but I know no shortcut for that one...

 

Somehow, I feel there is a bad ground. I disconnected the battery overnight and, when I reconnected it, the digital readout went from 9.9v to 18.4v, then to 16.2v. The battery, itself, is reading about 13.6v. Looks like I'm going to spend some time trouble shooting this problem!!!!

 

Call this guy Gene at http://www.corvettedashclusterservice.com/ He will set you straight.