I've had this on going problem for 3 weeks now, it started with the AC clicking on & off, did this a few times then shut off altogether, check charging system came up. Ok I took the alternater out had it checked by a very trustworthy alt,starter comp. they said the alt was fine, so I replaced the battery ( it was only 10 mos old ) it was ok for a few days when it happened AGAIN !!!!!! I took that STUPID alternater OUT AGAIN, had it checked, it was fine. WTF coulds the problem be, I don't want to bring the alternater to that guy again he'll think I'm NUTS !!! Any suggestions will be greatly appreciated........
Check charging system
- Thread starter Cubster
- Start date
driller
Dedicated LVC Member
Battery terminals, wire harness to regulator, power wire...
Run a heavy(4 guage) wire from the alternator output to the battery terminal or battery stud on the power distribution box.
Check ALL grounds.
Run a heavy(4 guage) wire from the alternator output to the battery terminal or battery stud on the power distribution box.
Check ALL grounds.
1wykdmk8
LvC Dues Collector
IT might still be bad. If it does not put out over 13V under load it is no good. I would put it on the car, start it up, and check the voltage output without anything other than the motor running, and it should be over 14v, and turn a few things on, and it should not drop below 13.5v. :Beer
I am having kind of the same problem. My amp for my subs is cutting off at idle, the the music not playing (volume dowm to 0 or paused). It's fine while driving. Had the altenator tested it put out 13.4 volts with nothing on.
Black87LSC
Dedicated LVC Member
With nothing on at idle, the alternator should be putting out 14.2-14.3 volts. Your alternator is probably on its way out.
driller
Dedicated LVC Member
Testing your charging system quickly with a digital voltmeter (assuming charged battery):
1. Test battery voltage with engine off. Check at battery terminals at clean terminal or clamp, not the bolt or nut. Record voltage. This is your battery's standing voltage.
2. Start engine & run at 1500 RPM. With no other load (doors closed? Underhood light off? Auto headlights off?) - record voltage. Voltage should be higher but not by more than 2 volts. This is your charging voltage without load.
3. Turn on heater or AC to MAX along with turning on highbeam headlamps. Increase RPMs to 2000 RPM. Voltage should be a minimum of 0.5 volts above your standing battery voltage. This is your charging voltage with load.
You can see the alternator voltage should be a minimum of 0.5 volts to a maximum of 2.0 volts above your battery's standing voltage. Less would be undercharging while more would be overcharging.
IF you see the 'check charging system' warning on the message center... something is really astray as the voltage needs to be below 9 volts or above 18 volts!
1. Test battery voltage with engine off. Check at battery terminals at clean terminal or clamp, not the bolt or nut. Record voltage. This is your battery's standing voltage.
2. Start engine & run at 1500 RPM. With no other load (doors closed? Underhood light off? Auto headlights off?) - record voltage. Voltage should be higher but not by more than 2 volts. This is your charging voltage without load.
3. Turn on heater or AC to MAX along with turning on highbeam headlamps. Increase RPMs to 2000 RPM. Voltage should be a minimum of 0.5 volts above your standing battery voltage. This is your charging voltage with load.
You can see the alternator voltage should be a minimum of 0.5 volts to a maximum of 2.0 volts above your battery's standing voltage. Less would be undercharging while more would be overcharging.
IF you see the 'check charging system' warning on the message center... something is really astray as the voltage needs to be below 9 volts or above 18 volts!
2001LS8Sport
Dedicated LVC Member
I would have your charging SYSTEM checked! Not just the alternator. Do it like they said above. But you also need to check for amps. Voltage is not amps and it's very possible to be charging the proper voltage but way down on amps. Any competent shop can do this quickly for you and shouldn't charge that much to do it.
67Continental
Dedicated LVC Member
the battery terminal check is very good idea, i had something similar happen on a pickup and it was just bad terminals.
94m5
Dmaup's Daddy
I had the same problem on my 95' Turned out the brushes on the regulator were cracked in half, but did'nt fall apart. This caused them to work sometimes, then not. I got a replacment regulator for 32 bucks.