[maxharvard]

With all the accessories on and car running, i've tested the alternator and battery with a multimeter.

At the battery i get a reading of 14.20
At the alternator i get 14.22

However, the gauge in the dash says 12.8-13.00. I've checked all my grounds and everything seems to be grounded well.

Ideas? Suggestions?

[Mister G]

Where does your dash mounted gauge measure the voltage? If it is not right at the battery you probably have some voltage drops due to resistance. Not knowing what type of DMM you are using i would still venture to say that unit is more accurate than a dash mount.

[JimM]

the best check would be to use yuor meter, and check the voltage at the guage. #'s agree, you have a voltage drop in the wiring, troublesome but not a huge problem yet if everything works right. #'s don't agree, car is good, guage is off. Again, not a huge problem.

[maxharvard]

True... the gauge is wiring directly into the harness... Everything does work well. I guess its a minor annoyance to have a gauge that doesnt work properly.

It just bothers me that i have a gas gauge issue as well, both are buggin the hell out of me.

[undee72Z]

Originally Posted by maxharvard

With all the accessories on and car running, i've tested the alternator and battery with a multimeter.

At the battery i get a reading of 14.20
At the alternator i get 14.22

However, the gauge in the dash says 12.8-13.00. I've checked all my grounds and everything seems to be grounded well.

Ideas? Suggestions?

Temp wire the gauge right to the battery, if its still low the gauge is off, if same readings as multimeter, either voltage drop or poor connections somewhere. How much difference in voltage if some or all of the accessories are turned off? Try cleaning the connections at the horn relay buss bar,

[Everett#2390]

I have noticed on alot of GM cars & trucks through the years, e.g., 88 Monte Carlo SS & 88 Chev C3500, GM in-dash voltmeter reads mid-scale, as designed.

MCSS reads 13 volts midscale. Chev reads 14 volts midscale. Both read 14.5 volts at battery & alternator. So, it could be the gauge scaling. If you ever get to the voltmeter source or voltmeter itself, this will tell the story.