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ray_mcavoy · 03-20-2014, 02:02 PM

No, it doesn't just run off the alternator. It reads the system voltage whenever the ignition is switched on. In other words, it'll show battery voltage with the key on / engine off and it'll show the alternator charging voltage with the engine running.

A common problem is the contacts on the printed circuit for the cluster plug. Even though the voltmeter shares the same power & ground circuits as the other gauges, it has it's own set of contacts & printed circuit traces. So a bad connection there will only affect the voltmeter and not the other gauges.

Check to see if the printed circuit traces have lifted off the plastic in the connector area and carefully glue them back down if necessary. Also check the contacts in the plug itself to make sure they're not bent or distorted. And use a test light or voltmeter to verify the power & ground connections (pink w/black stripe & black wires) to the cluster plug are okay.

If that all checks out okay, remove the front of the cluster, unscrew the voltmeter, and pull it out. There should be 2 metal clips in the cluster that made contact with the studs on the back of the voltmeter. Use a test light or multimeter to see if you have power between those two clips with the key on. If you don't have power there (and the cluster plug checked out okay), carefully squeeze the clips and pull them out. Clean any rust/corrosion off the clips & printed circuit contacts and snap the clips back in.

If you do have power at those two clips, check the resistor on the back of the voltmeter itself. Make sure the nuts holding it in place are secure (but not so tight as to crack the ceramic substrate). You can also measure the resistor with a mulitmeter ... If I remember correctly, they're close to 130Ω.

03-20-2014, 02:02 PM	#2
ray_mcavoy Registered User Join Date: Nov 2009 Location: Sherman, ME Posts: 2,373	Re: Battery voltage gauge no worky No, it doesn't just run off the alternator. It reads the system voltage whenever the ignition is switched on. In other words, it'll show battery voltage with the key on / engine off and it'll show the alternator charging voltage with the engine running. A common problem is the contacts on the printed circuit for the cluster plug. Even though the voltmeter shares the same power & ground circuits as the other gauges, it has it's own set of contacts & printed circuit traces. So a bad connection there will only affect the voltmeter and not the other gauges. Check to see if the printed circuit traces have lifted off the plastic in the connector area and carefully glue them back down if necessary. Also check the contacts in the plug itself to make sure they're not bent or distorted. And use a test light or voltmeter to verify the power & ground connections (pink w/black stripe & black wires) to the cluster plug are okay. If that all checks out okay, remove the front of the cluster, unscrew the voltmeter, and pull it out. There should be 2 metal clips in the cluster that made contact with the studs on the back of the voltmeter. Use a test light or multimeter to see if you have power between those two clips with the key on. If you don't have power there (and the cluster plug checked out okay), carefully squeeze the clips and pull them out. Clean any rust/corrosion off the clips & printed circuit contacts and snap the clips back in. If you do have power at those two clips, check the resistor on the back of the voltmeter itself. Make sure the nuts holding it in place are secure (but not so tight as to crack the ceramic substrate). You can also measure the resistor with a mulitmeter ... If I remember correctly, they're close to 130Ω.