Motorhome won’t start

Coach battery is either low or you need to clean the coach battery terminals or your coach battery needs replacing. Did you try starting the generator? Does you coach have an emergency start switch?

Just perform a full diagnostic as you would with a station wagon or SUV.

Keep in mind things do wear out. Not every electrical failure follows a series of tattletale intermittent malfunctions. Some things may just quit.

If a solenoid "clicks" it is one clue. If it loudly CLACKS it's another. Turn on the headlights. Someone needs to see them and report. Try to start the engine. Do the headlights go out?

If you tried boost with no success then you've already bypassed the couch battery so not the battery. Sounds like the starter went south or connection to starter is loose or corroded.

Farmboy666 wrote:
If you tried boost with no success then you've already bypassed the couch battery so not the battery. Sounds like the starter went south or connection to starter is loose or corroded.

Not necessarily, you are assuming that the boost switch contacts are not corroded (2000 DP) and that he held the boost down for a minute before trying to start. What happened to the headlights when you tried to start will tell us more than anything so far.

What does voltage read when the key is in the "start" position?

Agree, engage boost/combine switch to add more batteries. But, will not overcome bad (loose or corroded) connections at batteries or starter.

I had an intermittent start problem that I think resulted in me replacing an alternator when it was not needed. The battery cable from my solenoid to my positive post on my battery had a "do it yourself" battery post terminal bolt-crimped to the terminal. The cable had corroded under the bolt-down crimp and while it felt strong it was failing electrically. It allowed enough power through the connection to power lights and the door-open buzzer and key-in-ignition buzzer and such, but when you tried to start the engine, nothing. Even when you ganged in the house batteries, still nothing. This should have been my clue. The problem was not the batteries (which were fully charged), the problem was the connection from the engine battery to the solenoid. So even ganging the batteries could not overcome the poor electrical connection.

I replaced the foot-long cable with a new one with factory-crimped-and-overmolded connections. The battery cable from the negative post was also fraying (and much harder to replace as it went down beside the engine to wherever it connects) and I had my mechanic replace it also.

So I would check your electrical connections. Take them apart and clean them.

Steve

MEXICOWANDERER wrote:
Just perform a full diagnostic as you would with a station wagon or SUV.

Keep in mind things do wear out. Not every electrical failure follows a series of tattletale intermittent malfunctions. Some things may just quit.

If a solenoid "clicks" it is one clue. If it loudly CLACKS it's another. Turn on the headlights. Someone needs to see them and report. Try to start the engine. Do the headlights go out?

X2

Start at the beginning. On my rig the Battery Mode Solenoid was clicking when the ignition was turned on but it was not making good contact internally. There was current flow but the contacts were not making firmly, there were carbon traces and pits in the contacts and slop in the movers travel, which kept it from making full contact and allowing full cranking amperage to flow.

A simple test, maybe not conclusive but easy to do, it too will take two people to perform. One person turns the ignition on while the second person is at the solenoid and after the solenoid is engaged and the engine does not crank, jumpers the contacts. If the starter motor cranks, it would seem logical that the contacts of the solenoid are not making good contact and, therefore, not allowing full cranking power to pass.

Fact. . Shortly (like 2 years) my Coach would not start. Turned out to be bad connection (Needed cleaning) battery positive.. Long story is they used the wrong metal for the lugs.. I finally fixed it 9 years later and not I don't have that problem. but All I had to do was go down and clean it. 3 times in 9 years. 4th time it needed a new battery.

Our coach didn't start one time. We had it towed and the mechanics found nothing wrong. All they did was disconnect the battery for 30 minutes. I guess it's all about the computer catching up, LOL. It happened one time with our slides and my husband disconnected the battery for 30 minutes, connected battery an all was fine again.

D.E.Bishop wrote:

MEXICOWANDERER wrote:
Just perform a full diagnostic as you would with a station wagon or SUV.

Keep in mind things do wear out. Not every electrical failure follows a series of tattletale intermittent malfunctions. Some things may just quit.

If a solenoid "clicks" it is one clue. If it loudly CLACKS it's another. Turn on the headlights. Someone needs to see them and report. Try to start the engine. Do the headlights go out?

X2

Start at the beginning. On my rig the Battery Mode Solenoid was clicking when the ignition was turned on but it was not making good contact internally. There was current flow but the contacts were not making firmly, there were carbon traces and pits in the contacts and slop in the movers travel, which kept it from making full contact and allowing full cranking amperage to flow.

A simple test, maybe not conclusive but easy to do, it too will take two people to perform. One person turns the ignition on while the second person is at the solenoid and after the solenoid is engaged and the engine does not crank, jumpers the contacts. If the starter motor cranks, it would seem logical that the contacts of the solenoid are not making good contact and, therefore, not allowing full cranking power to pass.

Had a similar "hidden inside the clamp" corrosion issue at one of the coach batteries in my Roadtrek about 8 years ago. Noticed it felt a bit loose when checking connections at the batteries. Pulled the clamp off, pretty much fell off, stripped the insulation back past the corroded section and cleaned it up. Replaced the clamp connector. Success. Symptoms were low battery SoC status and genset wouldn't turn over intermittently.