My 1984 M1009 keeps draining the battery closest to the firewall. I swapped it out under warranty both batteries are brand new but if I do not start it once a week the rear battery goes dead. Anybody have any ideas?
If you have a good alternator shop nearby, I would remove Alt 2 (passenger side) and get it rebuilt. Be sure to explain it is an isolated ground alt.
Testing it for output, will not show your problem.
You can/should explain your problem, but it should not cost much to just replace the internals(excluding rotor and windings).
To test this idea(bad alt), you can carefully disconnect the red wire from the rear of that alternator.(do not touch ground with it or your wrench!) and leave it off for the next week. If the drain is gone, rebuild the alt.
Beat me to it, I agree with the above- Could be the alternator is doing it. Try removing the large wire that attaches the the passenger side alternator, leave the wire off for a week and see if the battery is any lower.
Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website like our supporting vendors. Their ads help keep Steel Soldiers going. Please consider disabling your ad blockers for the site. Thanks!