I have an electrical issue on my 04 V70 and I am trying to determine if the alternator is the culprit. My question is how to test the alternator, or rule it out. It is of course not a quick job to take it out, so I am thinking if I remove the heavy red positive cable, as well as the white/red striped wire(which I believe is for the regulator?), I could run the car essentially without the alternator. As long as the battery is good I think the car should run, and I think I could check to see if the electrical gremlins go away, and if they do I would know its the alternator. If I do disconnect the red cable will I be able to start the car?

A simple test for your alternator is to put a voltmeter across the red lead and a ground (the engine) and see what the voltage reads. It should be 13.5 to 14 VDC with the engine running.

There are only a few things that usually go wrong with an alternator, the brushes wear out (low voltage), the bearings fail (noise), or the diodes fail (low voltage or a lot of AC ripple on the DC). Bad grounds can cause them to act up too.

Greg

I kind of answered my own question. I did take the cable and wire off the alternator, and the car ran without issue. I then put them back on and started it back up and got a electrical system service required message. The gremlins have been intermittent, but I think I can logically say it makes sense to start with changing out the alternator.

Now if I could only figure out which one to buy! 140amp? 160amp? even then there are so many options. The one in my car is a cheapo reman, so I don't see any identifying numbers to make this easier.