Alternator Charging Problem?

[LT]

Okay yesterday it was raining really bad so I had the head lights on, the wipers going, the heater going and my stereo. My stereo kept cutting in and out whenever I turned on the blinkers, and the lights would dim and light up constantly on the face plate. After awhile my stereo stopped working and then my blinkers stopped working till I turned off the head lights.

I have a re-manufactured 80 amp GM alternator on my rig right now that I got in August. I'm going to check all the connections to the alternator, the fusible link on the battery post, and the post on the starter. I just re-wired my rig so all the wiring is brand new and I did not wire in the ammeter through the alternator. Any thoughts on what could be wrong?

Bad Alternator?

Bad Connections?

Or do I have a wire that is drawing too much power somewhere that I have to go find?

 

[chuglife]

i work in the parts dept of a GM stealership and we get those reman. alternators coming back in all the time. maybe take it to a parts store and have them bench test it?

i sometimes have a similar problem in the rain, where the alternator can't seem to keep up with all the stuff running... so i'm hoping to get some lower draw components such as LED brake lights and turn signals, etc. i find that the brake lights draw about the same amount as the headlights, the turn signals to a lesser extent.

 

[LT]

Napa isn't gonna want to refund my GM Alternator after the grinder attack to make it fit my 79 alternator mount

 

[Landpimp]

my 82 fj40 did the same thinig with the stock alt, I swaped it out for another OEM alt and all is well, the old one just wasn't putting out enough amps to keep up with all the stuff I had on. a 80 amp should be more than enough so I would guess its just not working right.........

 

[Yoda]

Make sure the belt is tight (shouldn't be able to slip the fan pulley with hand pressure).

 

[72cruiser]

i'm also running into alt/charge problems and i was wondering what are the best options for a replacement alternator out there....

i have a 2F and have nothing extra electrical on the cruiser right now (no radio, no winch, etc), just headlights, heater, turn signals and breaklights....
i am goin to put a winch on it in the future, and a cd player with an amp, so that would make a difference, right?


thanks,
malphrus

 

[LT]

I just checked all the grounds and found only one loose set that i could get to. Since I live in a apartment complex I don't think they would want anti-freeze all over the place when taking the heater off to really see everything behind the dash

I tried cranking over the engine and the battery is low right now so I have the positive battery cable off. So i'm thinking it's the alternator took a dump on me, so much for napa quality. I took off all the fuses to the wires that I did not use since I had a 16 circuit wiring harness and i'm only using maybe about 11 or 12 of the circuits.

We'll see, just when you think you've solved everything another problem arises

 

[Mace]

Charge up the battery and start the truck..

the post that is on the motor left side of the alt (looking at the back of the alt) is the lead that charges your battery. Get a Voltage reading on it.

It shoudl be about 12.5-13

If not, is it a internal or external regulator??

 

[mobi-arc]

Not sure if I understood the message correctly, but if you are trying to crank the engine, or have the engine started, then remove the battery positive cable, that's the absolute worst think you can do to an alternator; it's called a load dump and will cause the alternator voltage to go sky-high and can easily blow diodes. If I misunderstood your message, my apologies. Back in the days of generators, lifting the positive battery lead was a common method of testing. With alternators (as opposed to generators) lifting the battery lead is bad news, but this damaging method of troubleshooting is still around.

Scott

 

[LT]

Charge up the battery and start the truck..

the post that is on the motor left side of the alt (looking at the back of the alt) is the lead that charges your battery. Get a Voltage reading on it.

It shoudl be about 12.5-13

If not, is it a internal or external regulator??

It is internally regulated. The volt meter is back at my parents place

I'm going to go to auto zone and get it tested to see if it's shot or not.

You sure it's the left prong? I have the battery charge line on the right prong and when I first initially started it, the battery was going up in volts back in August. The left prong has the gauge lamp wire that came with the wiring harness (already pre-wired for delco alternators)

 

[LT]

Not sure if I understood the message correctly, but if you are trying to crank the engine, or have the engine started, then remove the battery positive cable, that's the absolute worst think you can do to an alternator; it's called a load dump and will cause the alternator voltage to go sky-high and can easily blow diodes. If I misunderstood your message, my apologies. Back in the days of generators, lifting the positive battery lead was a common method of testing. With alternators (as opposed to generators) lifting the battery lead is bad news, but this damaging method of troubleshooting is still around.

Scott

No I have not tried to take off the positive battery cable while it's running The battery is already low and barely cranks the starter, so I just took the cable off just in case it's getting drained from some wire I haven't seen yet that is sucking power.

 

[LT]

*UPDATE

Took the alternator to Auto Zone, just as my suspicion... it's fried Napa Quality