My 1996 xj6 alternator charging gauge showed a huge drop in the charging rate, so I had it tested and it showed the battery was good but the alternator was bad. I purchased a remanufactured alternator and spent almost six hours removing the old one and replaced it with the newly purchased one. Then came the big surprise after I started the car - the gauge still showed a failed charging rate. I then had it tested and again the battery was good, but the alternator was not charging. A bench test of the old alternator showed it in fact needing to be replaced.

Now I don't know what to do next. I do not look forward in removing the newly installed alternator to have it bench tested and then possibly find out that it is good and I have another problem somewhere else. Could there be a fuse failure somewhere between the alternator and the battery, or a bad relay or regulator? I need help. I really do not look forward to taking the newly installed alternator out to have it bench tested.

 

Good evening Terry.
I once had the same problem. What I found was a loose junction at the passenger side firewall where the positive battery lead from the rear of vehicle joins to the main lead underhood. You will find a stud which passes through with a nut securing the positive cable underhood and inside the passenger compartment. Grab the cable and check for tightness. If loose then disconnect the negative lead at the battery to prevent arcing then have someone hold one side with a wrench as you tighten the nut on other side.
I hope this helps!

Tom

 

Hi you could check Fuse 10 (5 amp) in the RH engine fuse box. This powers the Regulator.

Roger

 

Thanks for the tip. That fuse was good so I guess either I have a bad connection at the alternator or it is bad.

 

Are you sure it's spinning fast enough? My harmonic balancer failed with no squeal sounds, so the belt was not spinning. Found out while installing my third good alternator.

 

Rchiv, you were onto the right path with your suggestion. I had such a difficult time maneuvering the alternator into place when I installed it I must have pulled loose the terminal L plug which prevented the unit to charge. With great difficulty because of restricted space at the back of the alternator I was finally able to re-insert the plug. That was the answer. That's what I get for being such a poor backyard mechanic.

Thanks for your knowledgeable assistance. Everything is working fine now.

 

Glad to pointed you in the right direction.

Roger