Ground Wire, Not a Bad Battery

[Russ-USA]

Thought this might be useful to share.

I start our stored in the winter outside motorhome about every two weeks. Normally it starts up just fine and I warm the engine and charge the battery (winter in Wisconsin).

This time I turned the key and the starter could not even turn the motor over. It's a new AGM battery purchased last April. So I pulled the battery, warmed it up at home and charged it. Put the battery back in the rig and still no start. Just a feeble noise by the starter.

Took the battery to seller (Batteries Plus) and they load tested it and indicated the battery was fine.

Went back to the rig with the battery and cleaned all the battery terminals and then all the ground connections on the rusty battery bus welded to the battery compartment.

Still no luck.

Now I'm thinking either connection issues up stream or a starter.

Squirrel myself under the rig and check grounds and wiring until I get to the starter and find a ground connection to the frame that was loose. tightened that one down and like magic the engine turns over and starts like there was never an issue.

Interesting on how one little thing can stop you in your tracks...

Russ

[Morich]

Sounds like you tracked her down very well but I might add another place that can jump up to bite us if we are not aware of it!

We can look at the battery cables at the battery and spot the places where they corrode but there are also other spots which may hide from us and really give us fits to find! One of those on your RV is shown on the parts drawings here:
https://catalog3d.winnebagoind.com/menu/Parts.htm

There are several mega fuses along the cables at different points, some in the battery box and some hidden. That hidden one is outside underneath the RV on the frame and just behind the front right wheel. No spot one would ever expect electronic parts, right?

Those mega fuses are an incoming connection and an outgoing connection and either one being corroded will kill the power, so be aware of them when chasing problems!

[Russ-USA]

Excellent point! I did leave out that I also looked at the fuse connections also. Was surprised to see the one on the frame as you indicated. Very exposed to the elements. There are two more in the battery box. All possible fail points. Probably would not hurt to do periodic maintenance and go over all the connections from time to time.

[DavidM]

I am surprised that there was a chassis ground in the starting circuit. For at least 30-40 years, vehicle manufacturers have stopped using the chassis as a ground circuit to avoid exactly the problem you had. But maybe F53s still use the chassis as a ground.

David

[Russ-USA]

Just a clarification. The ground point was next to the starter, but I really do not know what was being grounded. That wire was in a harness and did not directly connect to the starter housing that I could see. However, once tightened the starter functioned as expected.

[deckape]

It's always the ground .

[MadMaxWinny]

Yup. Nine times out of ten, low voltage failures are a bloody faulty ground.

[Kvw613]

We’ve been bitten by the same thing, after thinking it was the relay and then the starter. Multiple connections to the same ground post. Vibration, dirt, water, rust, oil all contribute. Clean and tighten periodically.

[xjaywalker]

WOW!!! Great info....That hidden fuse! Awesome..Getting ready to do some chassis rust clean up and will be checking our all the grounds. I hate surprises..