Gen light always on

cuttyman

Not-quite-so-new-guy
Aug 3, 2014
14
8
3
#1
My generator light never goes off .... Not running i have about 12.3 to 12.5 volts . with vehicle running it reads 14.2 roughly. Is this light on because its overcharging ? I definately have no issues with the battery dying or having low power but this stupid light is always on . the volt gauge in cluster tends to read between 10 and 13 when running but a voltmeter on the battery says otherwise . even when the meter in cluster reads over 13 the GEN light never goes off . the brightness of the GEN light also seems to vary a bit . has anyone experienced this issue or know where to start ?
 

Jeff L

Master Mechanic
Nov 20, 2016
494
378
63
Southern AZ
#2
I remember many many years ago my 73 buick had that issue. No gauges in the car, just the idiot lights. Battery was checked and ok. Replaced the alternator and problem was solved. It had something to do with the voltage regulator.

Not sure this is your issue, but very similar to mine.

Just remembered that was also a time my headlights and dash lights would dim or get brighter depending on the engine rpm. That issue was fixed when the new alternator was installed.
 

pontiacgp

Canadian Prime Minister
Mar 31, 2006
22,260
3,328
113
Kitchener, Ontario
#3
Sounds like the charging system is working properly. I think it may be a problem with the wiring or the cluster's circuit board since the gauge isn't working properly either..

I just read your other thread about the tachometer not working properly either. I think that problem is related to this one and there is something going on with the circuit board
 

cuttyman

Not-quite-so-new-guy
Aug 3, 2014
14
8
3
#5
I remember many many years ago my 73 buick had that issue. No gauges in the car, just the idiot lights. Battery was checked and ok. Replaced the alternator and problem was solved. It had something to do with the voltage regulator.

Not sure this is your issue, but very similar to mine.

Just remembered that was also a time my headlights and dash lights would dim or get brighter depending on the engine rpm. That issue was fixed when the new alternator was installed.
I was thinking the voltage regulator as well like maybe it was overcharging slighlty . but my voltmeter showed 14.2 at battery at idle . thats pretty standard if i recall correctly . im about to just pull this stupid light out . lol... It seems like there is an awful lot of idiot lights missing allready.... The only ones that are plugged in are the gen brake and seat belts . Also one random one that is blacked out on the panel. Lights missing are engine , hot , fasten seat belt , water in fuel , low fuel , check engine , lights on , wait. Im guessing some are for the diesel option but shouldnt there be some for engine , hot , low fuel and lights on ?
 

pontiacgp

Canadian Prime Minister
Mar 31, 2006
22,260
3,328
113
Kitchener, Ontario
#7
I was thinking the voltage regulator as well like maybe it was overcharging slighlty . but my voltmeter showed 14.2 at battery at idle . thats pretty standard if i recall correctly . im about to just pull this stupid light out . lol... It seems like there is an awful lot of idiot lights missing allready.... The only ones that are plugged in are the gen brake and seat belts . Also one random one that is blacked out on the panel. Lights missing are engine , hot , fasten seat belt , water in fuel , low fuel , check engine , lights on , wait. Im guessing some are for the diesel option but shouldnt there be some for engine , hot , low fuel and lights on ?
if the voltage regulator is charging too high turning on all the accessories and lights would draw the power down and if that was the problem your light would go off. Charging at 14.2 volts is not too high.
 

Jeff L

Master Mechanic
Nov 20, 2016
494
378
63
Southern AZ
#8
I remember back in the old days the way to fix an idiot light on the dash that would not go out was to stick a piece of electrical tape over it!

Seriously look for some bad/exposed/dried out wires and circuits others have posted. If you can get the alternator tested at a parts store it might be worth a look. Been a while so not sure who still has the free testing available?
 

cuttyman

Not-quite-so-new-guy
Aug 3, 2014
14
8
3
#10
Sounds like the charging system is working properly. I think it may be a problem with the wiring or the cluster's circuit board since the gauge isn't working properly either..

I just read your other thread about the tachometer not working properly either. I think that problem is related to this one and there is something going on with the circuit board


Thanks everyone for your input.

I will double check the board but i didnt notice any breaks in my first glance . i will also check the lights later tonight as i haven't driven in the dark for awhile so not sure about the dimming dash lights .
 

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