Altenator not charging


Asked by R Jun 26, 2020 at 12:22 PM about the 1994 Mazda B-Series B4000 SE 4WD

Question type: Maintenance & Repair

My battery isnt charging. I have no system
drains when car is off (tested with
voltimeter). With volitmeter i get a strong
voltage reading from hot wire on alt to
anywhere on engine and neg battery
clamp i get a tone from positive bat clamp
to hot wire and one prong on the three
prong connector leading to alt. The middle
prong tones to the single prong connector
to alt (not the hot). Ive replaced the alt and
charged the battery full and i still get a
votlage drop when i start my car and evem
a bigger drop when i rev my engine. Im
thinking i got a bad altn as it was a reman.
But they benchtested it and they say its
fine. I replaced fuses and checked
connections. Sorry for the book but im  at
a lost.

2 Answers


This is a pic of the type of alt i installed no ground wire on mine tho. Grounded through chassis im assuming


Well ive done alot of testing and researching and ive found some useful info buried out theren. Ive not solved the problem but i think i just about got it.. On 3 wire alts the green wire is very important it runs through the fuse box to the dash panel to a battery indicator light. Test this you should get 0v with key out but same voltage as battery with engine off but key on.. This wire tells the alt to work. So could have good alt good bat but alt is just being told to relax its not needed. And almost every alt issue that got far enough to make it to these forums this seemed to be the answer just most people never came back to share. Chances are i might do the same some assume i was right if you dont see me.... Dont judge no one posted anyway ive been talking to myself the last couple days. Honestly and sincerely, Nadda Mickanick

Your Answer:

CarGurus Experts

  • #1
    Michael Tutty
  • #2
  • #3
View All

Find great deals from top-rated dealers


Related Models For Sale

Used Ford Ranger
9 Great Deals out of 846 listings starting at $1,999
Used Toyota Tacoma
25 Great Deals out of 653 listings starting at $1,966
Used Ford F-150
150 Great Deals out of 5,919 listings starting at $2,995
Used Mazda MX-5 Miata
55 listings starting at $7,995
Used Jeep Wrangler
30 Great Deals out of 617 listings starting at $6,795
Used GMC Sierra 1500
87 Great Deals out of 3,378 listings starting at $3,900

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use. Content will be removed if CarGurus becomes aware that it violates our policies.