Voltage at fuse block?? (1 Viewer)

[Derf62]

We measure 9.9 volts at fuse block (with engine off). Shouldn't this be 12 V?
"71 FJ 40, 2 battery system with both batteries fully charged. Truck starts /runs fine.
Trying to add a plow with electric controller, but controller not lighting up.

 

[middlecalf]

Should be whatever voltage your source is, which is your batteries with the engine off. What’s their voltage? If not 9.9 V, rather 12.8+ if fully charged as mentioned, then you have a current draw somewhere.

 

[snaggletto]

Bypass all factory wiring. Wire directly to the battery with a new fuse close to the battery. Hacking into an old electrical system can be bad news.