Panzer9

Anyone care to chime in on this problem? When cold it registers as it should- When up to normal operating temp, though, the needle is dead. I have noticed I need a new battery- It's been dying lately just from running my CD for a few minutes on Auxillary. The Alternator charges it up in short order though... Thank you!

joejoe

Does warning light come on? It should be lit when key is turned to on position (not started). If when running and warm even though it may be at low spot it still charging. Check volts at battery and jump post with ohm meter. Both mine will show different readings during running. When checked with meter they are always at 13.5 or so.

Normy

The voltage gauge on these cars tend to be flaky. Do any of your other ancillary gauges give you trouble? The printed foil on the back of the instrument cluster is usually the problem. I have the same problem as you do; I just ignore it.

N!

tomcat

If you are taking short trips the alt may not be fully charging the battery. Especially noticable when it gets cold when starting need the power the most.

JPTL

I noticed a 'flaky' tach needle a while back. It would stick at a certain point, regardless of increase in rpm...then it would jump up to the proper reading.
It hasn't done this for a while, however.
Maybe you'll get lucky and it will stop acting up.

SharkSkin

When it's "dead" as you say, with the car up to temp, are you idling with both fans running? Does the voltage improve with RPM? The battery may be really gone. If your alternator is working too hard, especially at idle(low voltage, high current) then it won't last long. Clean up all the grounds, battery connections, terminals at jump post etc. and start from there. Any signs of water ever leaking in on top of/behind the fuse/relay panel?

Jerome Craig

Hey buddy... I have a very similar problem. My voltage starts off at about 13 and then drops below 12 after I've been in the car for maybe 10 minutes. If I don't give it a little gas when I stop, the voltmeter will drop to 10. (I need to adjust my idle as it is usually down around 400rpm) If I keep the revs at about 800rpm~850rpm it'll stay steady at "about" 12. It won't go up to 13 unless its been parked for a couple of hours. Neither my dash lights, nor my headlights dim when the meter reads low, conversely they don't get any brighter when I rev up. I going to replace my battery this weekend.

BTW, I cleaned all my grounds and that actually made a huge difference in the voltmeter reading. Prior to cleaning the grounds my voltmeter would stay around 10 volts.

Maybe we can compare notes on Saturday if you're coming out to Rockville.

Panzer9

While cold, the needle reads as it should, however once the car is up to operating temp, the needle is inop. I have noticed that I will need a new battery shortly ,as simply playing my CD for a few minutes on auxillary kills it. The Alternator I assume is good , since it recharges the battery in a short period of time while driving. Any suggestion, opinions, or solutions greatly appreciated. Thanks!

Panzer9

Thanks for the responses,guys. OK Here's the deal... When cold -starting- she fires right up, and the needle reads approx. 13.5 V. However, once up to regular operating temp , the needle suddenly goes dead. It doesn't fluctuate w/ RPM's, no warning lights, All other gauges A-OK, nor does my car "run hot". I made sure the ducting tube is securely in place, too. ??

Mike Frye

Panzer,

I'm with JoeJoe who asked, 'How about the warning lights?'. Are you getting any other indication that the guage is wrong (obviously you don't have zero voltage if it's running) but if the warning light is working but doesn't indicate low voltage I'd be inclined to think it's something loose in the guage/pod/grounds.

If you also get a warning light or a VOM shows the voltage low/fluctuating when running you probably have a different problem.

If you know you need a battery anyway, it might be best to replace that and clean up all grounds before trying to chase one symptom.

SharkSkin

Very strange -- the feed for the voltmeter should not be affected by engine temp or anything else in that way. It could be cross-wired, or it could be a bad connection. If it were me, I would be tempted to pull the cluster and hook the voltmeter straight to 12V and see if it quits reading after a few minutes. If so, replace. If not, trace it back until the source of the problem is found.

Randy V

Try cleaning the battery contacts and the negative battery ground strap attachment to the body first.

JPTL

I'm guessing here, but I had concluded that the problem with my jumpy tach needle was a bad/compromised connection. This might be your problem.
Since the signal to the gauges is likely in the milliamps, it probably doesn't take much to compromise the connection and make it misbehave.
This was the case with the airbag fault that I experienced a few years back. It wasn't a bad sensor, it was simply that the connection at the sensor plugin wasn't quite what it originally was. I guess it was putting out too much resistance, and throwing the fault. The connections looked perfect & new, but after spraying some contact cleaner on the contacts as well as the ground to the sensor @ the chassis, I cleared the code and the fault hasn't appeared since.
I don't know how hard it is to get to the connections to the guages, but spraying them with contact cleaner (nothing but contact cleaner) can't hurt.

Jim M.

The Voltmeter connects to a 12V supply in the dashboard. Turn the ignition on without starting the car; the voltmeter will indicate battery voltage MINUS any voltage drop from the battery to the voltmeter. Depending on the condition of the battery and the state of the wiring it should read 10.5 to 12.5V. While cranking the engine the battery voltage falls due to the heavy load of the starter and your voltmeter will indicate the drop. When running, the alternator supplies charging current to the battery and powers the electrical sys. It produces a higher voltage than the battery. The voltmeter will now indicate the alternator voltage MINUS any voltage drop from the alternator to the voltmeter. Depending on the alternator output, the battery condition and the car's wiring it will read 13 to 15V. An aid in fault diagnosis is knowing where the needle normally sits, before and after starting, to see a difference if you have a problem with your battery or alternator. Tested the 68-ohm resistor for the alternator excitation circuit, this is the white rectangular component that sticks out of the back of the instrument cluster. Check any replacement, if it's off by more than 2% geta refund. Soldered it into the sockets. All parts should be tested (when practical), before installation.

Jim Mayzurk
93 GTS 5-spd

rmr25

Mine does exactly the same as yours. To ease my mind as to what the voltage regulator was doing, I found a cheap digital voltmeter that plugs into the cigarette lighter socket. It tells me I'm usually getting 13.5-7 volts at start and slightly lower when running normally.

I found my meter here. http://www.cetsolar.com/voltmeter.htm
I think it was about $15 shipped.

In the meantime, I now have the gage cluster out for shift indicator light issues! Maybe I can solve the cluster voltmeter problem while in there.