Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 11, 2025 ...

Why did my HWH #3 (battery) fuse BLOW?

July 24, 2020, 01:45:48 pm

After over ten years of ownership, the #3 (15amp) fuse inside the 9" by 14" aluminum box for the HWH control boards BLEW! I do not know why but would like to know.
Here is what happened: My 96 U320 was parked for a couple months when I wanted to lift the coach off the front tires. I pressed the 'AIR" button on the dash HWH panel, the "active light" turned on, then slowly went out.  Nothing would work. Opened the HWH box located on the rear wall of the basement compartment behind the front wheel on the driver side. The #3 (battery) fuse was blown and I replaced the fuse. All manual functions now work and I am confident that travel mode will work.

MY QUESTION: Is the #3 fuse blowing an indication that there is an intermittent error in my HWH control boards, which will cause this #3 fuse to blow repeatedly until I fix this intermittent problem?

I searched the Forforum and found references to repairing the HWH boards, but nothing about what causes #3 fuse to blow.

Quote Selected

Re: Why did my HWH #3 (battery) fuse BLOW?

Reply #1 – July 24, 2020, 02:27:12 pm

FWIW, my personal "fuse" theory, developed from decades of working on cranky old cars:

When a fuse blows once - replace it and get on with whatever yer doin'.

If it blows again, figure out why.

Fuses get old.  Sometimes they just let go for no discernible reason.  Stuff happens.

Quote Selected

Re: Why did my HWH #3 (battery) fuse BLOW?

Reply #2 – July 24, 2020, 02:45:41 pm

Often a common reason for a blown fuse is trying to operate something on a low battery.  As voltage goes down, amperage draw goes up.  I've often seen this, a fuse protecting electric slide out motors, customer would call me to say the dxxx slide out will not work.  My first question was, "have you had a low battery lately".  RV mfgs eventually said to start the generator when putting electric motor powered slide rooms in or out.

Quote Selected

Re: Why did my HWH #3 (battery) fuse BLOW?

Reply #3 – July 24, 2020, 04:56:05 pm

Jack beat me to it. 2 for  Low voltage.

Quote Selected

Re: Why did my HWH #3 (battery) fuse BLOW?

Reply #4 – July 25, 2020, 01:27:14 pm

While my solar panels keep the batteries fully charged when parked, it is possible that bad wiring or dirty connectors is causing low voltage at the HWH box. I will investigate the possibility of low voltage!

Quote Selected