Alternator not charging battery 1985 240dl

OntheDL · Post by **OntheDL** » 07 Jul 2025, 16:32

I recently changed my water pump and alternator on my 1985 240. Before I even drove a half mile the dash lights all lit up. Getting charge from the battery but not putting out current to charge the battery. The B+ is not increasing to 14 the D+ is not even getting a 1/2 volt whether the key is turned on or running idle. Any ideas of what could be causing the problem?

Vova585 · Post by **Vova585** » 07 Jul 2025, 17:43

Question 1: do you still have old alternator?
2: why you decided to replace alternator if old was good? (Just my assumption)
3. Check if all connections are tight.
4. Check voltage drop test for positive and negative side.

Most likely you new alternator is defective(was good before, installed new and now problem..)
In case you need guidance on troubleshooting this issue go to "scanner danner " youtube channel he has several videos on this topic.

Post by **volvolugnut** » 07 Jul 2025, 19:32

Likely you have a bad connection at the alternator or left a wire loose when installing.
Is the belt installed correctly and still tight? Is the belt wet?
Is the alternator correct for the Volvo?
volvolugnut

OntheDL · Post by **OntheDL** » 12 Jul 2025, 10:21

Thank you for the suggestions. I fiddled around with the wires inspecting them. I think I am pretty sure what the problem is, the wires for the exciter and oil pressure sensor. have attached a photo of the wires they are at the position of under the crack case. I Any suggestions where to find replacement or splicing?

Post by **volvolugnut** » 12 Jul 2025, 15:33

Cut out and replace bad wire with crimp connections covered with shrink tubing. Even better, use soldered connections covered with shrink tubing.
Cover the finished wires with new split wire harness cover.
volvolugnut