Angie-

A common problem on the 850/X70 cars is a voltage drop on the positive side of the charging system. I have gotten into the habit of checking for this while doing a service, and almost a third of the cars have this problem, even if there is no 'complaint' about charging or weak/dead battery. I make it a point to check for this if the car has had a battery replaced recently. With the car running, turn on the rear demister, headlights, and heater fan to high speed. Connect a volt meter between the alternator B+ and the battery positive post. The voltage shown on the meter should be less than .3 volts. If the drop is too high, the alternator can't keep the battery charged, and the battery dies a slow death- it may take years for it to finally fail. There is a bulletin on replacing the cable, but I think I have a better solution than replacing one defective part with the same thing. I solder the connection where the cable is crimped to the terminal at the battery. So far I have had a 100% success rate.

Dave the Volvo Tech

'99 V70R AWD, '93 854 GLT, '82 242 DL