Voltmeter Fluctuating??
Thread Starter
Melting Slicks
Joined: Dec 2006
Posts: 2,669
Likes: 3
From: Kingston Ontario
Voltmeter Fluctuating??
I have not had a chance to troubleshoot this yet. Thought I would throw this out to the forum, for some advise.
While driving when the turn signals are turned on, they work fine; however the voltmeter drops a complete volt and returns to normal. Voltmeter follows the load on, off ,on, off, as the signal light is flashing. (13.5 v., 12.5 v., 13.5v., 12.5 v, etc...)
This not only happens with the signal lights but also if a load put on, by turning on the heater fan the voltmeter goes down slightly and when the heater fan is turned off the voltmeter returns to normal.
Normal operation the voltmeter reads approximately 13.5 volts.
Component or wiring issue?
TIA, Dan
While driving when the turn signals are turned on, they work fine; however the voltmeter drops a complete volt and returns to normal. Voltmeter follows the load on, off ,on, off, as the signal light is flashing. (13.5 v., 12.5 v., 13.5v., 12.5 v, etc...)
This not only happens with the signal lights but also if a load put on, by turning on the heater fan the voltmeter goes down slightly and when the heater fan is turned off the voltmeter returns to normal.
Normal operation the voltmeter reads approximately 13.5 volts.
Component or wiring issue?
TIA, Dan
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
I suspect your battery might be weak in holding a full charge or maybe the alternator is not able to adequately keep up with the electrical system.
Drive down to a local parts store, and have them load test the battery and alternator.
Drive down to a local parts store, and have them load test the battery and alternator.
Thread Starter
Melting Slicks
Joined: Dec 2006
Posts: 2,669
Likes: 3
From: Kingston Ontario
I can have them checked out on Monday, but would not mind seeing if I can find the problem tonight or tomorrow. 
Put a multimeter to the battery and shows 12.5 v. Start car and it reads 14.2 volts. Turn signal on and the car voltmeter guage does as before, bounces one volt as turn signal operates. Check the multimeter at the battery and it reads a steady 14.2 volts. Weird, expected to see the same result as the voltmeter.
So, does my multimeter not respond quick enough to the voltage fluctuation or it is possibly a wiring issue or guage malfunction?
Put a multimeter to the battery and shows 12.5 v. Start car and it reads 14.2 volts. Turn signal on and the car voltmeter guage does as before, bounces one volt as turn signal operates. Check the multimeter at the battery and it reads a steady 14.2 volts. Weird, expected to see the same result as the voltmeter.
So, does my multimeter not respond quick enough to the voltage fluctuation or it is possibly a wiring issue or guage malfunction?
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Bad gauge/dashboard ground....need get in behind with a jumper and go from black wires/instrument frame to ground on bird cage or maybe engine/frame....
that will prove it, you need then find the bad connection....rust, loose, broken off,
that will prove it, you need then find the bad connection....rust, loose, broken off,
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
Its pretty normal for it to do that. Your digital meter cannot capture the fluxuation on DC mode. See if you can find an analog meter somewhere, doesn't have to be fancy. Most systems the voltage will drop a bit with an increase in load. It could also be a sign of an alternator with a bad diode trio in it.
If its charging and lights are bright, you got no problem
If its charging and lights are bright, you got no problem
Thread Starter
Melting Slicks
Joined: Dec 2006
Posts: 2,669
Likes: 3
From: Kingston Ontario
Its pretty normal for it to do that. Your digital meter cannot capture the fluxuation on DC mode. See if you can find an analog meter somewhere, doesn't have to be fancy. Most systems the voltage will drop a bit with an increase in load. It could also be a sign of an alternator with a bad diode trio in it.
If its charging and lights are bright, you got no problem
If its charging and lights are bright, you got no problem
I know I still have an analog meter buried in the workshop. I was hoping I may have a bad connection somewhere that would cause my symptoms and I would have had a quick fix.
So, if I show a fluctuation with the analog I can assume the alternator is the culprit? Would this be an indication of imminent alternator failure?
