Cummins ISL400 runs and quits... questions

Ivylog wrote:
Marc, how did you figure this out? Did you call Monaco? Another reason for not wanting a monoplex system.

I didn't exactly figure it out. I was guessing.

You are right, the Intelletec Monoplex system is very complex. There are a lot of neat things about the way it works but if you get a gremlin... good luck. The whole coach is controlled by this monster.

The house switches were acting glichy. They were flashing lights in the wall panels that didn't make any sense.

The house and the chassis electrical interface with each other so I thought maybe there was a short or bad ground somewhere in the house system that was feeding over into the chassis.
That's why I disconnected the house side just to see if that might do anything. It was my last guess.

It appears that disconnecting the batteries for the 40 mile drive to the service center has reset everything (at least for the time being). The house system is now acting normally and the engine runs with the house turned on.

I spent all day with a tech going over everything and the only thing he found was the battery isolator relay is bad. It is a part of the Intellitec system that basically allows both house and chassis batteries to charge when the engine is running.

The House side isn't charging and the "Big Boy" relay (yes that's what it's called) was humming and clicking and got very hot while the engine was running.
He said that it could possibly be pulling the EMS down below 10 volts which would shut the engine down.
He's just guessing though because it wouldn't repeat the problem and throw a code that would identify where the problem was.

So.. that bad boy will get replaced and we'll see if that's it.