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Username Post: "generator" light stays on while engine is running.... (83 1/2 pickup)        (Topic#342909)
World Domination 
Contributor
Posts: 531

Reg: 03-01-08
02-26-17 09:00 AM - Post#2678593    

83 1/2 pickup
My generator light stays on while the engine is running. It seems 1/2 as bright as compared to the brake, choke and oil pressure warning lights.


What i've done so far:

1) Measured battery voltage at 12.5, then started the engine. No change in voltage.

2) 2-3 hours later, tested alternator output with the engine running with the voltmeter. Red probe to the B+ terminal and then black probe to the body of the alternator. So with the engine off, 12.4ish and with the engine running no change.

3) i test lighted both wires in the plug that plugs into the top of the alternator (terminals 1 and 2 or "R" and "F"). With the ignition on; Both wires have power, but the smaller brown wire (terminal 1 or "R") is dimmer than the larger red wire (terminal 2 or "F").

So, i used the voltmeter; The larger red wire has 12.4-8 ish while the smaller brown wire, 6.3-5 ish.

4) i jumpered terminals 1+2 while the engine was running and the plug plugged in. The battery stayed at 12.08 V

And as far as i can tell the gen light stayed on, again seems 1/2 lit compared to brake, oil, choke lights.


Next?



 




wagonman100 
Super Senior Member
Posts: 14002
wagonman100
Loc: Baltimore, MD
Reg: 11-27-04
02-26-17 11:30 AM - Post#2678614    
    In response to World Domination

Your voltage readings should be higher with the engine running. I'd say you have a bad alternator.

Jay
Some days it's not worth chewing through the restraints.

1999 Silverado Z71 4X4 extra-cab short bed
1983 Malibu Fauxmad - tubbed
1978 El Camino Kustomized
1972 Monte Carlo
1957 210 handyman wagon
1957 Nomad sport wagon


 
acardon 
Ultra Senior Member
Posts: 11020
acardon
Loc: DFW TEXAS
Reg: 03-25-05
02-26-17 01:16 PM - Post#2678635    
    In response to World Domination

  • Quote:
Next?



Take the alternator to a auto supply and have it tested.

Don
66 Corvair (driving)
57 2dr HT (driving)
56 2dr HT (waiting to be restored)


 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17178
grumpyvette
Age: 70
Loc: FLORIDA USA
Reg: 03-16-01
02-26-17 04:39 PM - Post#2678668    
    In response to acardon

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


 




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