Posted by Don Williams [172.68.78.168] on Friday, December 02, 2016 at 07:00:12 :
In Reply to: Ok auto electrical smart folks answer me this posted by Bruce in dank,wet, B.C. [108.162.245.77] on Thursday, December 01, 2016 at 19:33:03 :
Had a very similar problem on '77 M886. Chased it for quite a while. The voltage fluctuation was causing an on-board inverter to cut out due to over voltage. Finally determined that the voltage sense wire was reading low due to voltage drop through an almost 40 year old wiring harness. Fix was to run the voltage sense wire from the battery +, through a relay on firewall, to the alternator. Used the ignition on circuit to turn on the relay. Voltage is very stable now.