I am having a problem with the car not charging. We replace the alternator 3 times but that hasn’t seemed to fix the problem. I dont know what wlse it could be. Any suggestions?
Have you tried replacing the battery and/or checked the battery connections from the trunk to the engine bay firewall?
Chevy …
You said that you’ve replaced the alternator three times. Why? Did you have the alternators tested and found them defective each time ? Over what period of time did this happen ?
Either one of three things is happening :
-
The alternator is not charging … alternator easily tested. Also check all grounds and connections
-
The alternator is working but the battery won’t hold the charge … check/replace battery
-
Everything is working but something is draining the battery charge … find the parasitic drain
1 Like
We just bought new battery. Still doesnt charge. The alternators the first two were tested bad then the third time i made sure it was tested it came back good. Amd this happened over a span of 3 months.
Have you actually measured the battery voltage across the battery terminals when the engine is running to check that the alternator (assuming it is good) is trying to charge the battery?
You should see 13.8V to 14V with the engine at idle with none of the lights on.
Over the years, there are many reports in the XJ40 archives of problems on '93/'94 cars with the battery in the boot, of corrosion on the battery positive lead as it passes through the firewall via a terminal post. Access in the engine bay is reasonable but much more difficult from inside the cabin but if that terminal post is heavily corroded it will not pass current through so the alternator output may not be reaching the battery to charge it.
I don’t have a copy of the XJ40 Haynes manual now, but I believe there is a section in there describing how to check the alternator output on the car.