My 2002 s60 had to be towed tonight from my work parking lot because it would not start. The battery appears to be fine. When I turn the key over, I hear just a single click, but the car does not start. Any ideas as to where the problem may be- bad starter or ignition switch and how do I go about determining the source of the problem?

 

what check did you do on the battery exactly?

when mine did the same thing it was the alternator. it would click and engine wouldn't turn. seems to be a common problem.

before knowing what it was i tried a fresh battery and it worked for a short while but because the alternator was not charging it properly it died again soon after.

if you can maybe get a hold of a good battery try it and if it starts it must be your alternator.

 

I replaced the battery (original 9yrs old) and the car started, however two day later, exaxct same problem, engine will not turn over. I talked with the dealer, and he said to look at the small wire on the starter to see if its loose, however that does not make sense if it starts then it doesn't start. It appears to me that the battery is not charging properly, how do I know if the alternator is bad?

 

shouldn't be the starter as you said.

the new batter helped a little but it only takes a few rides with radio, lights and AC on for the battery to be drained again if the alternator is not doing it's job properly.

If you have a tool you can use to measure what the alternator is charging but you could probably go to any shop and have them look at it.
They will probably say it's not the whole alternator but a small part(common problem), but because they have to take it apart it's gonna cost you the same so they'll recomend a new one(actually refurbished one).

i paid about 260€ with labor in Spain not sure how much they will charge you.

 

The small part that goes bad is the regulator that bolts to the end of the alternator. If you can take the alternator off a shop can just replace the reg. for a couple of hundred dollars. Hook a voltmeter to the battery leads of the fender well and if you don't have approx. 14.5 volts with the engine running the alt. is not putting out.