Alternator test

[cuda-cable]

What's an easy test to check the output of my alternator, i have a volt meter wired direct to battery but see only 12 volts, drops to 11 with headlites/heater on. I never see anything greater, just started driving car last week, but don't want to get stranded with a dead battery far from home if my alternator isn't charging. I don't have a 'large wire' ground from engine to frame? could that be my problem?......will try that in the interim.......thx.....dk

[matt63]

You can check the alternator output voltage at the big lug on the alternator.  It should be about 13 to 13.5 volts depending on the regulator.  Many common repair shops or battery places can do a load test on the charging system too.

[Chryco Psycho]

you should be as high as 14.2v , did you try revving the engine with the voltmeter connected ?

[FY1 RT SE]

Do you have good grounds at the voltage regulator and at radiator support?

[cuda-cable]

folks,  thx for all the good suggestions, I've added a #1Ga ground from my engine block to the frame......things are much improved, dash lites in particuliar and I'm showing 14+ v on my gage. You folks are a huge help......thx......dk

[MEK-Dangerfield]

Congrats!!


   You definitely nailed it!!         


  Mike

[71 DEPUTY]

if that helped I would check the main ground cable from the battery to the block- if it is really old it could have some resistance inside the cable.

[inot2old]

Glad your problem was just a ground.  I had the same problem, & ended up replacing the voltage regulator which solved it.