Alternator going out?

[RacnJsn95]

Starting Thursday night, the "charge"/batt light in the dash has been lit up (dim, not full on lit) when the car is running. If you rev it up it get's dimmer, but never goes out... I'm suspecting that the alternator is going bad, but I guess the battery could also be not taking the charge?

Using my multimeter, were would be the best place to check the voltage coming out of the alt?

I did stumble across the rebuilding the LR160(?) alternator, and am contemplating doing it myself, or calling the local alt rebuilder down the street and ask what he'd charge me... Napa wants $175, but I have to give them my core to be rebuilt... Seems high. Plus Napa would have to send it out for who knows how long and I'm suspecting the car would be down for at least 2-3 weeks.

[kassim503]

I would point to the alternator being faulty, you can measure voltage from the back stud of the alt. and ground it to the batt post.

NAPA should be sellin the remans for 60 a pop, but you dont get your unit back. I just guzzle through remans until i get a good one, thats what the 1 year warranty is for, just keep your reciept.

[RacnJsn95]

You wouldn't happen to have a part number for that would you? They told me $175, but they would need mine first because no one has any cores for it

[asavage]

Measure the alternator output between the stud on the back of alterator where the 10 ga. white wire connects, and the alternator case. Do not use the battery terminal to check the alternator first. If the voltage at the alternator is reasonable (13.8-14.6v at a fast idle with all accessories OFF), then turn on the headlights (high) and heater fan (high), retest the voltage and note it. Move the negative probe to the negative battery terminal (not the post) and recheck: is the terminal voltage lower than the first check at the alternator? Wiring. Then move the negative probe to the battery post. Voltage lower? Bad battery terminal or corrosion.

Then move the positive probe to the battery terminal etc.

I put my money on a failing diode (though there are some fairly wimpy connectors between the alternator and the battery). You're read my post on the LR160 and LR150, seen the broken diodes. Every one I've been into have had bad diodes.

Replacing the diode assy requires a decent soldering gun (140W or better; a 300+W gun is best). If you want to attempt rebuilding it yourself, round up the parts first of course. You can buy the brgs locally (but you'll need a split brg remover to get the idle-end brg off the rotor), I've listed the NAPA/Standard part No. for the brushes in the LR160 thread, but it may take a bit to get the seal and diode assy. I stock both, if you need them in a hurry, otherwise order them from Townsend Electric, which is where I buy them.

I just rebuilt my last LR160 core for a member, and doing it myself, buying quality parts, I paid about $80 for the parts, (the core was $25 at the JY). That's with non-Chinese brgs, new brushes/diodes/seal.

When shopping NAPA, make certain to buy the parts whose part No. does not begin with a '2'.

Checking NAPA's online site, NAPA seems to have discontinued stocking rebuilt alternators for this application, but do list two part Nos (NAE 14586, and PME 14586: I do not recognize either line code, but they sure aren't Raylock).

[RacnJsn95]

Thanks for the help everyone... Hopefully I solved the problem, I'll know tomorrow when I drive to work. Turns out the wire that goes to the post broke off at the connector I re-attached it, so we'll see if that does the trick.