Today I was trying to figure out the alternator voltage sensor wiring on our 97 270. I found the correct schematic and was pleased to see that this one is wired correctly. Anyhow, for future searches and my own documentation, here are a couple of photos. The first shows the exciter terminal (green arrow, wire E6) and the voltage sense terminal (red arrow).
The voltage sense wire is E59. It terminates at the 20 amp circuit breaker on the isolator board. Looks like the one with the red arrow pointing at it. Could be located anywhere on the isolator mounting board.
jor
John, We wired the sense wire directly to the start battery positive terminal with an inline fuse. More direct is more accurate. Connecting to the breaker is probably a convenient place to find a fused connection. Many have had problems from corrosions and poor connections. I cable tied a PVC pipe to the frame members to carry the single wire from street-side to curb-side.
I'm thinkin' that's a good idea. What size fuse did you use? Thanks.
jor
John we are not at the motorhome, so I don't know the fuse size. I assume it to be low, like 1 amp installed near the battery. It has never blown and is in place to protect the wire itself from a short. I will check when we next go to motorhome. Thinking about it, it may be better to have an auto-reset breaker.
Because it is a low-amp draw, there is no need to go all the way to the chassis battery. The large gauge wire from battery isolator to chassis battery should have zero voltage drop across it. Yes, this ASSUMES clean, tight connections.
So electrically, either location for the sense wire is the same.
The sense wire on our coach is direct to the solenoid on starter
JohnH
Wow, that isolator board looks factory new. Do you know who refurbished it? Nice job.
Mine looks all rusty and dirty.
Mine was the same. I just blasted and painted it. I moved it up under the bed so I'm hoping to keep it from returning to its previous state.
jor