https://volvoforums.com/forum/showthread.php?t=29851

After reading this post, I am having the exact issue on an 01' C70 where:

*Car died after daily driving in front of the house, battery read 9V.
*Pulled / Tested battery at auto store, bad battery (3.5 years old).
*Replaced with volvo battery.
*Voltage only reads 11.7V at the battery while the car is running and doesn't seem to charge (assuming the alternator is bad also)
*Car broke down again where it will start but not drive due to some electrical issue, voltage is 11.4V at the battery (Strange lights on dash, but no low battery indication?)

So how do I tell if it's the Alternator OR Regulator? And is the Voltage regulator INSIDE the alternator?

Any help appreciated...THANKS

 

I am not expert but I think that all you need is voltage regulator and it is part of the alternator. Here is link

 

is the Regulator inside the alternator, or are they totally separate parts ?
Also, does the Volvo S70/C70 have a 100 amp alternator or 80amp ?

 

The regulator is PART of the alternator, but looks simple to replace.

http://jameyroe.com/downloads/C70_Alternator.jpg
http://jameyroe.com/downloads/C70_Alternator_Top.jpg

I chose to drop mine off at the local auto electric shop, they confirmed bad voltage regulator and is $117 out the door.

Not bad considering the part is $70-150 and it will be bench tested right BEFORE I reinstall it in the car.

Hopefully this does the trick, it took me 3 hours to get the alternator out since I've not removed the belt / power steering pump before. Thank goodness my hands are SMALL!

 

I'm having a VERY similar case with my 2000 C70. Had to jump (one year old) battery and it was fine until I turned the car off a half an hour later. AAA battery service shows up and their 5 minute test with a printout says that the battery is "severly discharged" but the altenator is fine. Said to have a trickle charge done which I did at a service station and he also said the alternator looks fine. But later that day it died again -- at AutoZone -- where I had bought the original battery. That guy did a test which said the battery is dead and alternator is fine. Got a new larger battery (first one was probably too small) and two days later the car cut out while I was driving! It would not keep a charge - an it was just two days old! Had it towed to my volvo guy and now he's telling me that it needs a new alternator which costs $500 for the part and $200 to install!!!

Did anyone figure out if its possible to tell if the voltage regulator is bad, separate from the alternator?

 

This is interesting......so I spoke to my Volvo guy who originally wanted to charge me $700 to do the alternator and I came back and suggested doing just the regulator. He said OK that will be $330 (but then he'll probably bust my alternator just to prove he's right and I'll have to pay the remaining bucks!!).

I took a look under the hood today (its sitting dead in this guys lot) and the alt looks a bit buried and tough to get to. Does anybody have any step by step info/diagrams (or maybe a video) on replacing an alternator in a 2000 C70?? This might beyond me. Thanks again!

 

Update -- last night under the cloak of darkness I went to the to see if I could find where the battery cable meets the fuse box (for any corrossion) but I must have been looking in the wrong place - couldn't see it. But I jumped the car for about 5 minutes. It started fine, put on the lights, the radio and the Ac -- still fine. Took it down the street about 300 yards and I felt a loss of power, the ABS and STC lights came on, then about 15 seconds later the ROPS (roll bar) and SRS lights came on (but no generator/battery light). The car stayed running, the lights stayed on(dimmed) but there was no response from the accelerator! Wierd. Does this sound familiar to anyone.

 

In my opinion it sounds like the low voltage is what caused the ABS and other light to come on.

One old school way to tell if an alternator was putting out is to pull the positive battery cable from the battery with the car running.], if it instantly dies then it's not putting out.

The regulator is built into the alternator, I would do a search for a local shop that can rebuild it, the ones at AutoZoxx are crap, the rectifiers are notorious for being defective right out of the box or soon after.

I know someone who has one now and driving at night is nerve racking " all the lights pulse ".

The alternator isn't real hard to change.

Hope this helps.

 

I called my guy and told him to do just the voltage regualtor (he called it a brush pack) instead of doing the full alternator. It worked! And I paid $330 as opposed to $700. Its disappointing that they wouldn't have gone that route first.

 

~Chief Rambo~ a alternator is only $120 at AutoZone, $180 for the original Bosch alternator from IPD the Volvo specialist. Can be annoying to install, but satisfying ince you accomplish it..does require multiple wrenches. I would never pay a mechanic more than $100 to install a alternator, $75 would be a decent deal.