1994 940 Alternator

sickboy · Post by **sickboy** » 13 Feb 2019, 17:07

Alternator is not charging.
Cleaned wires and posts at battery. Did a voltage check on positive wire from alternatoe, ok. Did a voltage drop test on positive and negative wire from battery to alternator. OK. Ran a new exciter wire from battery to switch, from switch to alternator male spade connection with a 50V, 1 Watt diode inline with voltage (gray end) towards the alternator.
Nothing works. Went through six alternators. Three from Autozone, three from NAPA. Last 2 were new and not rebuilt. I do not know what else to do other than pushing the car into the bay. Any help would be appreciated.
I bypassed the battery light in the instrument panel because of instrument panel electrical issues.
I have the Volvo wiring book, complete. I ran bypasses to the ground and positive wire on the alternator, still nothing, Replaced the battery. Nothing. I cannot get a charge. Any advice before I go for the 7th alternator?

lummert · Post by **lummert** » 13 Feb 2019, 18:55

Curious to know if the alternator ground wire is connected.

sickboy · Post by **sickboy** » 13 Feb 2019, 22:04

Blue wire from alternator to ground (engine) is connected. Ran another wire from battery ground to alternator housing bolt. Still not charging. I cannot believe six new alternators are bad. It's only 3 wires. Battery, Ground and exciter wire.

940tvolvo · Post by **940tvolvo** » 14 Feb 2019, 10:38

I don't know but I am having the same problem, what I am having to do is polarize the alternator, I have a wire with 2 alligator clips one on each end of the wire. With the car running, I clamp one onto my positive battery and take the other end and touch it to the bolt closest to the edge of the alternator (sorry do not know what that bolt is called). After I do that my alternator starts charging my battery, but If I don't do that then alternator does not charge the battery. So whatever I am bypassing by doing that I am assuming is my problem and might be yours as well.

sickboy · Post by **sickboy** » 14 Feb 2019, 15:45

Fixed. Called the company that makes the alternator. They told me how to wire it. Ground was on the wrong post. Exciter wire went to a new post also. Had to change the female spade connector on the exciter wire to a round post type connector.