I have a 2006 S40. I had the timing belt replaced along with a few other smaller items about six months ago. Two months after that, all the lights flashed and I was left sitting in the road. Bought a new battery and put on a used alternator (new one was $800) and 2 months after that, I was left sitting in the road again. Luckily, the used one had a lifetime warranty.

Meanwhile, I have this issue of my AC blowing cold, then hot, then cold air. The pattern is when the AC is basically only blowing hot air, the alternator is getting ready to die.

I desperately need your help as a single mother with no other car to drive! Don't tell me to go to Volvo, I can't afford it. I do have a very good, honest mechanic but is kind of dazed as I am.

Is the belt too tight? Is the air compressor causing issues with charging? Is it an electrical problem?

Ideas?

 

Turn the AC off?

 

I am not sure I understand where you are going with that school of thought. I could ride with my AC off but how am I going to determine if that is what is causing my alternator to die?

 

Welcome to the forum!

When the voltage gets low in our cars they tend to do strange things. At this point, though, the alternator is already dead and you are running on battery power alone until it's too weak to supply the car. That's when you get the weird behavior and flashing lights. The amperage demand in modern cars is very high. I'm surprised alternators live as long as they do. I'd bet money you simply got a used alternator that did not have much life left in it. (Did you see a red battery symbol on the dash before it died?)

Do you live near a city? If so, find an alternator rebuilding shop. In my little city of Knoxville, Tennessee we have a place that will rebuild any alternator for about $35-$50 depending on type. They will even paint it for $5 more.

If you are forced to buy a reman from an auto parts store then get the lifetime warranty version. At least if it goes bad you can take it back for an exchange.

EDIT: There is a separate issue of the a/c compressor needing to be shimmed. When the shims are not adjusted correctly the a/c will do the cold - hot - cold cycle. However, it has nothing to do with the alternator. Just throwing that out in case you fix your alternator and the a/c continues to cycle when it's not expected.

 

Thank you for your response.

Unfortunately, I have one of the $800 rare alternators that you can only buy from the dealership. My mechanic and I tried to find someone to rebuild it but was not successful. I would love to have it rebuilt!

I do not have any warnings when the alternator is getting ready to die. No red battery light. This last time, all the lights came on and I immediately pulled over to the side of the road. After sitting there for a few minutes all the lights went off and I could drive another minute or two before all the lights came on again. The first message to flash is "power failure". Then power steering off, airbags off, service required immediately.

A friend came and put jumper cables on the car for about 5 minutes and then I was able to drive about 30 minutes to my home.

 

Try this site. They have alternators for much less than $800. I've bought parts from them before with good results.
VOLVO S40 ALTERNATORS & RELATED 2000-2012 at Swedish Auto Parts

 

This is a known problem, we had it in our 06 S40. There was a recall to install new software. A work around is to advance the temp control completly to HIGH. Then turn the temp down to desired setting. The AC control sytem will then work, until the next time.....