How's it going guys, sorry for the up coming long thread but I need some help. As the title says I think my ECM is pulling voltage when the truck is off. History of the truck, its an 86' MJ with a 92' 4.0 and AX15 inside. Lately I have been having an issue of a dead battery over night, which is worse than usual for this truck, usually its at least a week. But anyway after finally getting fed up with it I pulled the negative cable, and jumped my multimeter between the negative terminal and negative cable.
I pulled every fuse under the dash, only one had an issue, and that is the dome fuse, but it only pulled 1 volt. So I went to the distribution center under the hood, pulled everything until I got to the Engine Control fuse, unplugged it and the voltage dropped to only 1 volt being pulled total now.
Plugged fuse back in and unplugged the computer, still was pulling 9 volts, got my service manual out to try find what else may be on the Engine Control fuse, found the transmission control module, the truck use to have an Aw4 behind the 4.0. So I unplugged that while the ECM was unplugged and voltage dropped to 1 volt total pull again. Then I plugged the ECM back in and it was back up to 9 volts.
Anyway my question is, does anyone know what an ECM should pull when off? Could my ECM be junk?
I pulled every fuse under the dash, only one had an issue, and that is the dome fuse, but it only pulled 1 volt. So I went to the distribution center under the hood, pulled everything until I got to the Engine Control fuse, unplugged it and the voltage dropped to only 1 volt being pulled total now.
Plugged fuse back in and unplugged the computer, still was pulling 9 volts, got my service manual out to try find what else may be on the Engine Control fuse, found the transmission control module, the truck use to have an Aw4 behind the 4.0. So I unplugged that while the ECM was unplugged and voltage dropped to 1 volt total pull again. Then I plugged the ECM back in and it was back up to 9 volts.
Anyway my question is, does anyone know what an ECM should pull when off? Could my ECM be junk?