Voltage light on won't charge battery

turbo chris1970

Engine bay
Here's the situation , I have a new battery ,alternator ,from a spring tune up recently the light came on and the battery was charged and alternator tested so what could be the issue ? I fired her up after the charge and test and she ran fine with the light is still on so what is the problem guys please help thanks Chris from philly
 

GNVenom

Well-Known Member
If the VOLTS light is on and the alternator is spinning, you have a defective alternator.

Check to see if the light is on, key on engine off. The once you start the engine, does it go out briefly, then back on? It points to a bad regulator.

Be sure the alternator is spinning, and belt not slipping.
 

No disintegrations

Well-Known Member
On a Tahoe I worked on; it would intermittently charge and then not charge. When I brought alt to store for core return we tested it and it passed but still was no good due to intermittent nature. Make sense?
 

dynoman

Well-Known Member
Makes sense to me cause I deal with it almost every day. Components appear to be fine under initial load but fail after prolonged use , then "reset" themselves after "cool down" like nothing ever happened. It will slowly start charging less and less then it will eventually fail completely .
 

turbo chris1970

Engine bay
Tha
If the VOLTS light is on and the alternator is spinning, you have a defective alternator.

Check to see if the light is on, key on engine off. The once you start the engine, does it go out briefly, then back on? It points to a bad regulator.

Be sure the alternator is spinning, and belt not slipping.[/QUOTE thanks
For that info I plan to check her out in the morning I'll pm you with the results
 

turbo chris1970

Engine bay
Have any of you cats heard of the volt bulb that has a diode in the bulb casing and is the. Only one of the bulbs in the dash which has one of all the bulbs of its kind ? I've heard this in another thread from the board that it tells the alternator to charge and when and when not to charge the battery! Any thoughts?
 

Heskahoka

Supporting Member

Gene Van Horn

Active Member
Do you not have a volt gauge? If your battery tests ok, and your alternater test ok then your bulb in the dash could be not making comtact as it should. When my car did this, the volt gauge would go from good to bad sometimes when i hit a bump, i searched and searched and tested and tested and finally friend of mine tapped on the dash and the gauge would go up and down as the bulb made contact. No contact, no charge as the bulb completes the circuit.
 

turbo chris1970

Engine bay
See page 3 of this document.
http://www.installationinstructions.com/FYI/alternator_charging_tech.pdf

That bulb is no longer available.
See page 3 of this document.
http://www.installationinstructions.com/FYI/alternator_charging_tech.pdf

That bulb is no longer available.
That was the info I needed I took apart my dash today and got the bulb out and check the board for any imperfections thank you so much for sending that after all we are keeping these GM legends alive again thanks
Chris from Philly pa
 

Royal-T-Ltd

Well-Known Member
I use a Caspers field fix harness to bypass the bulb and not have to worry about weird charging issues.... just a thought... it's plug and play. - aaron


Sent from my iPhone using Tapatalk Pro
 

DR BOOST

Technical advisor
exactly^^^ and the maker of the the field fix unit came on here to tell him his problem is a bad alternator.
 
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