If I can jump in with another battery mode solenoid fail - with a twist...
1. RV is a 2008 WB Aspect 26A on a Ford V10 Chassis.
2. Had this solenoid fail a couple days ago, 2500 miles from home in the middle of a month long road trip. At least it failed in a family members driveway...
3. Figured out the problem, and tried finding a solenoid. It is still really hard finding things in these Covid times. Local (in a small NH town) NAPA could not find a Cole Hersee 24213 ("not available anywhere in the region"), but they did cross it to a suitable NAPA ST90. They found one in Boston, and over-nighted it here. The ST90 is 110A rated continuous, which is still higher than the 80A I found listed for the original Trombetta.
4. Removed defective solenoid, replaced with the new, fired up the engine, and the coach battery was indeed charging off of the alternator. Cool.
5. The family wanted to go for a ride, so we loaded up and headed out via a small RV park where I could top up the propane. Drove 20 miles (without stopping) pulled up to the park office to advise we wanted propane, went to move the RV... nuttin. Gauge lites worked, but no starter engagement.
6. Puttzed with OBD codes (P1000 - generic smog system failure), checked starter relay fuse, computer fuse, removed the coach battery connection to reset the computer, nuttin.
7. Just when I was ready to call a tow truck, a Mechanic from the RV park came by. He first jumped the started solenoid at the starter - the RV fired right up. OK then, starter is good...
Then he proceeded to check all the fuses - and the ignition switch fuse was bad! This was spite of (most) of the dash lights remaining functional. Changed the fuse, and it started right up.
It is not a coincidence that the ignition switch fuse is also where the power for the Battery Mode Solenoid comes from.
In review... I installed the new 4-post solenoid, it tested fine, we started and ran the RV 20 miles, and then after turning it off - or maybe upon the restart - the ignition fuse blows???
One of the last things I did before the Mechanic showed up was to pull the 12VDC power that feeds the Battery Mode Solenoid from the ignition switch. At this point I am hesitant put the relay back in operation; but at least now I have a nice sized fuse connection...
The factory "flyback diode" (to prevent over-voltage spikes on removal of power) does appear to be in place; but I have no easy way to test it. But fuses function due to over-current conditions - not transient high voltage.
While a pita, as long as we stay at places every 3rd day or so that have power - or we decide to run the generator to charge the house batteries - we can continue without problems. Would be nice though to figure this out though.
Ideas? Or maybe this was indeed just a coincidental time for that fuse to blow?