If this has been mentioned elsewhere, I apologize, I just found this board and wanted to post and thank the admins for making this sharing of Volvo love possible.

Two years ago I bought a '91 240, and was pleased to pick it up so cheap. I've been addressing the small things that have popped up (water pump, new belts, new battery, etc), but the largest challenge now is the charging system.

It'd been working fine for many months, then it sat for a bit, then when we cranked it back up, it would drive then die, no charging to the battery. Battery replaced, then crank, only 12.5 on the battery posts - time for an alternator. New alternator, same problem. Now, we can only drive the car during the day, as when the lights are turned on (or anything else that puts a drain on the electrical system) it kills the battery and the car stops in the road after the expected sputter. A jump will get you about 5 miles down the road, then die.

I pulled the new alternator out and had it tested, no problem there, but I still do not see 14-14.5V on the multimeter when the car is running.

I know my way around a car decently for a weekend mechanic, but I'm unsure where to go next ... voltage regulator, some electrical leak, etc. I've heard that the 240's have power running through the ignition switch and a bad ignition switch can cause this, but without a costly replacement (costly in time as well as parts) I do not want to go there until I have better proof.

 

my daughter's 87 240, had similar symptoms. I initially thought it might be the regulator/brush assembly, so I replaced that, nope, still no good. started poking around with volt meter... engine ground to alternator B+, 12.7 or so volts, no good. alternator body to alternator B+, ooooh, 14V! yay! alternator wasn't grounding properly, due to excess corrosion on the ground lead. new ground wire, and good as new.

the alternators themselves rarely burn out, 80% of the time, they just need new brushes, which come with the regulator assembly, and are a quick 2 screws from the back of the alternator. only time I'd replace the actual alternator would be if it had a bad bearing, or if the diode board inside the alternator has failed.

the "rebuilt" alternators you get from places like Autozone aren't much better than cleaned up and new brushes, quickly tested, and sold.