Hello all! I've been following this site for years and never had a reason to post. I bought a 1989 240 Wagon last year (after previously owning a 94 850!) and completely love it, even though it is like having an autistic child...

The car was as is, and looked like a rat had lived in it. I had to rewire all the stereo connections, clean up some exposed wires from around the instrument panel, including grounds, and pulled up the carpet to get to even more chewed through wires. I fixed the wire connections on the trunk struts (which always break over time I've learned) and rewired fog lights.

My recent problem is I started losing power driving to work the other day and at first thought it was an alternator problem because the battery was still powering the stereo. When I disconnected the negative cable on the battery the alternator shut off. Although at one point when I did this it kept going!!!

The oil light and check engine light come on when I start the car, but the BATTERY LIGHT does not. I talked to a Volvo specialist and he said that the battery light needs to come on to power the alternator. (I checked the bulbs,and connection on cluster is fine)

I removed the alternator, got it tested, it was good. I replace the Bosch voltage regulator with a brand new one, and tightened the belt. I checked the ignition switch with another, it was good. Checked the ground wires around the alternator and all look in good condition, and even check all the grounds by the instrument cluster. All fuses inside the car getting power.
Still fails tests at advanced auto parts--the computer says bad alternator.

It seems that the little red wire on the alternator is not getting power for some reason. My car will not pass emissions because the battery (BRAND NEW) dies during the test. The first time it didn't pass emissions was because they said it wouldn't go into 4th gear--(I replaced OD relay, checked solenoid power, and checked connections to shifter) The car has delayed engagement in shifting gears, but I was told that I may just need to flush transmission fluid.

I'm thinking that the OD problem is electrical and is tied into the alternator problem.

Why isn't my alternator charging? Is there a bad connection in the wiring harness on the tranny? Could it be a bad diode in the alternator?

Please help! I love my car and really think its something simple I can fix without paying an electrician...!

 

Could be a bad diode in the alt. You should never disconnect the battery while the engine is running.

Check the little red wire behind the alt. It comes from the BATT light through the gray connector on the firewall. Sounds like that red wire is bad.

 

That red wire is probably the culprit. Even though your car was built after they corrected the crappy wiring harness issues, it could be broken or shorted. The PO of my car cut off the old wire (still in the harness) and ran a red wire from the alternator, around the back of the engine bay to the disintegrating gray connector. I suspect it was to fix just such a problem.

 

Thanks guys! I will try grabbing another harness from a salvage yard today. Also though, is it possible that the circuit board for the speedometer is shot somewhere?