2000 V70 XC Alternator Voltage Problem

txt00 · Post by **txt00** » 10 Aug 2009, 21:36

I was driving my car with 137Kmi and all of the sudden, most warning lights appeared on the instrument clusters. The engine shut down soon after, and I couldn't crank the engine. I tried to jump started, but the car didn't hold charge and shut itself down again as soon as I put it in gear. I had to changed the battery to drive home. Here are some of the troubleshooting I have done so far.

1. Removed the alternator and tested at Advance Auto Parts (result came up negative with only about 11V output).

2. Bought a new reman. alternator from Bap Geon. Installed it and drove for about 20-30 minutes. Own my way home, some warning lights started to appear again, and the battery was almost drained when I pulled onto my driveway. I checked the voltage at the battery with the engine running and came backed with a range from 7-11v.

3. Test possible cable connection issues. Both connections on the back of the alt (thick cable and thin wire) were tight. Checked voltage on the thick cable and it was the same as the battery. Check voltage on thin wire with ignition switch in position "II" and it was about the same as the battery.

4. Battery warning light was not on when the ignition switch is in the "II" position. Removed instrument cluster to check the bulb. As a precaution, I swapped a known good bulb from another indicator (e.g. brake light) with battery warning bulb. Put it back together and still no battery indicator light when ignition switch is in the "II" position.

5. Decided to remove the reman. alternator and have it tested. Test came back negative with only about 11v. Also bought another alternator from the junk yard from a 99' XC70. This test came back with a correct voltage (~15v), but the diode test failed. So, I concluded it's probably not the test equipment.

6. Called Bap Geon to get a replacement and had it tested prior to installation. Took it to a different Advance Auto Parts, Napa, and Pepboys for testing and all came back negative. What's strange is Pep Boys had one on the shelf, and the test was negative on that one also.

My next step is probably have my old one rebuilt for about $125 which is slightly less than the reman. one ($155). Is there something I missed during my troubleshooting. Any inputs would greatly appreciated. What voltage should I expect to see with a good alternator. I would probably say around 14v.

Post by **Ozark Lee** » 10 Aug 2009, 23:15

I'm not sure who Bap Geon is but since you already shelled out the money for a rebuilt to them I would stay on their butt until they got it right.

That said, I have a couple of spare cars at the moment and I could afford to fight with them with no loss of mobility.

I think you've already got all of this tested / fixed but, at least on an 850, if the alternator light on the cluster burns out you get no charge to the field coil on the alternator.

...Lee

txt00 · Post by **txt00** » 11 Aug 2009, 05:50

Bap Geon is a local import auto parts store. I bought two alternators from them to test them out, and none gave me a correct voltage. The one from Pep Boys also didn't give a correct voltage when bench tested. Is there something with the Volvo reman. alternators that are not giving the correct results when tested?

Post by **Pauloil** » 11 Aug 2009, 20:09

volvo alternators are to be tested under load when in the car.
i'm not sure how you would load test one on the bench.
also, take apart your positive battery cable and clean all the parts with steel wool

Post by **Pauloil** » 11 Aug 2009, 21:13

this is from volvo 850 service manual:

OUTPUT TEST
1) Ensure connections at battery, generator, and starter are
clean and tight. Ensure generator, engine and body are properly
grounded. Ensure generator drive belt is tight and in good condition.
2) Connect ammeter following manufacturer’s instructions.
Connect voltmeter leads to battery terminals. Run engine to 2000 RPM.
Adjust carbon pile on tester until voltmeter reads 12 volts. Generator
output should be 49-55 amps. (55-amp generator), 63-70 amps (70-amp
generator), 31-80 amps (80-amp generator), 81-90 amps (90-amp
generator). If generator output is low, replace generator.

txt00 · Post by **txt00** » 13 Aug 2009, 21:37

Problem solved. I took it to the alternator repair shop and they replaced the regulator on the back of the alt where the thin wire connects to. I noticed that when bench tested, there will be a slight delay (few seconds) before the regulator kicks in to tell the alt to start charging. It's hard to believe all 3 reman alternators from the auto parts turned out defective when bench tested. Anyway, the car is back on the road again. Thanks for all the help.