Alternator / charging fault, 2004 v6

[PhilyC]

Evening all, quick one to find some likely scenarios.

Battery light has been coming on every now and again, enough for me to plan to check it out properly this weekend.

This morning, car started fine, battery light on solid, drove it down the street and vsc, track, check engine, abs, and downhill assist light came on one after another in sequence. I turned around and just as I got back it all just died. No juice.

Swapped the battery from my wife's car into it, started but battery light still on.

My thoughts are that the alternator has had it (don't know how old it is) so bought a new alternator and belt (may as well whilst I'm in there).

Firstly the alternator bolts are completely over tightened, I can't get the out. But I cleaned up all the terminals (the one at the back of the alternator belt on with a 10mm nut was badly corroded) and put on the new belt.

Tried it again with a different battery and it starts fine, no battery light and showing good voltage.

I now have my old battery on charge so atleast I can take it somewhere to get the bolts loosened if needed.

Question is, could it have been the belt/terminals or should I still replace the alternator?

I don't have a multimeter here, military so only here for a short time and without most of my tools.

Any + all thought welcome.

Cheers!

 

[MikeinNH67]

Evening all, quick one to find some likely scenarios.

Battery light has been coming on every now and again, enough for me to plan to check it out properly this weekend.

This morning, car started fine, battery light on solid, drove it down the street and vsc, track, check engine, abs, and downhill assist light came on one after another in sequence. I turned around and just as I got back it all just died. No juice.

Swapped the battery from my wife's car into it, started but battery light still on.

My thoughts are that the alternator has had it (don't know how old it is) so bought a new alternator and belt (may as well whilst I'm in there).

Firstly the alternator bolts are completely over tightened, I can't get the out. But I cleaned up all the terminals (the one at the back of the alternator belt on with a 10mm nut was badly corroded) and put on the new belt.

Tried it again with a different battery and it starts fine, no battery light and showing good voltage.

I now have my old battery on charge so atleast I can take it somewhere to get the bolts loosened if needed.

Question is, could it have been the belt/terminals or should I still replace the alternator?

I don't have a multimeter here, military so only here for a short time and without most of my tools.

Any + all thought welcome.

Cheers!

It can be dirty terminals but that will often make for a no starter scenario. Basically turn a dome light on, hit the key and the dome light goes out, often to come back on once the connection re-establishes.

You could have an intermittent alternator, brushes worn enough to touch sometimes. Beware, aftermarket alternators have turned into crap. I just buy lower mileage used OEM ones now and they always work.

 

[thennen]

It can be dirty terminals but that will often make for a no starter scenario. Basically turn a dome light on, hit the key and the dome light goes out, often to come back on once the connection re-establishes.

You could have an intermittent alternator, brushes worn enough to touch sometimes. Beware, aftermarket alternators have turned into crap. I just buy lower mileage used OEM ones now and they always work.

Agree with Mike on alternator brushes. A replacement set is $25 and will last another 180k miles. Very simple to replace once the alternator is in your hands. This has become a pre-200k maintenance item for me.

 

[SocalSam]

My battery light came on so I rushed home and measured voltages. Battery was good. Charging voltage was high. It started and ran fine so I drove to NAPA and bought a rebuilt Denso for around $200. While doing the install, I noticed a couple of wires had been mice damaged. Not sure if the wires were related to charging issue. Anyways, all good now.

 

[Brian513]

Sounds like classic alternator trouble. The corroded terminal or loose/old belt could easily cause intermittent charging and trigger the warning lights. Since it’s now showing good voltage and no battery light with a clean connection and new belt, your alternator might still be fine. I’d monitor it over a few drive if the light returns or voltage drops again, swap the alternator. Otherwise, corrosion and belt slippage were likely the culprits.