Starting Issue on a 2020 New Aire with Cummins ISB on Freightliner

[stankiyota]

I am having trouble getting my motor coach to start.

I have a 2020 Newmar New Aire on a Freightliner chassis with the Cummins ISB 6.8 diesel engine. The engine batteries are one year old and fully charged (they are on a trickle charge right now) at 12.9v. The generator starts fine from the engine batteries. All systems in the coach work fine on generator. The coach house batteries are fully charged at 13v

When I push the Start button on the drivers dash panel, everything lights up as it should. I hear a "relay" click twice as if it is trying to tell the starter to start the engine, but then nothing. The starter does not engage or even try to crank the engine.

Thoughts for troubleshooting before I call a Freightliner/Cummins tech?

Thanks.

Stan

[R.M.A]

Check the battery cables and battery chassis/ground. Also you could have a bad battery. Try the easy stuff first.

[SafariBen]

Do you have a multimeter? do you know how to use one?



Start at the battery, have a helper turn the key to start, does the battery voltage stay above 12v? what does it do?



Can you find a wiring diagram that would show where the start relay is? That would be the next place to check, if there is power getting there, and/or if the starter will crank if you supply power to the solenoid FROM there.



Unfortunately, it's probably not the battery, or the starter, but something in between that's harder to find. Was there any history to this problem? or just happened out of the blue? One method is to shut everything off, walk away for a while, then try it again after a while.

[Caliber]

Do you have a remote start switch in the engine bay? Try starting from there.

[vito.a]

You cannot determine battery charge level with a charger connected. Disconnect the charger and let the batteries rest for a few min. Then measure the voltage directly at the batteries with a voltmeter. If there are two batteries, disconnect them from each other and check each individually.
If it they still measure 12.6-12.8 volts you need to start cleaning the terminals and checking solenoids.
Also, the Cummins ISB uses a heater grid for cold starts. You need to turn the key to the on position and wait for the heater grid to heat up, then crank the engine.
Best of luck!

[OMMM4747]

A couple of things to try and consider ...

Is your rig equipped w/a BATT BOOST switch? It is designed to use the house batteries to aid the chassis batteries start the motor. If you have one, read your manual first to understand it operation and then try starting to rule out the starter, ignition relay, etc. If the engine doesn't turn over it's not your chassis batteries and something w/your starting system.

If it starts w/the BATT BOOST, I'd suspect a bad chassis battery (or 2). Just because they have 12.9vdc doesn't meant they're healthy enough to crank the engine. Think cranking amps. Have they ever been totally discharged/dead or exposed to prolonged extreme cold? Even if not fully discharged or extreme cold, it could be an internal battery failure. I once had a months old battery go dead for no reason. Took it back to the place of purchase where they ran a test to confirm it was bad and gave me a new battery.

Also ensure all the contacts are on tight and clean; no corrosion. Since you say they're relatively new, it could be a loose contact. If this was a DIY battery replacement did you connect everything correctly? I was on a thread a few months ago where the OP reconnected his new batteries incorrectly.

Good luck

[zrock2010]

if you have a helper have someone tap the starter it may be stuck/bad. Also the suggestions of above testing the batteries if it will not start with the boost function front the house battery's your starter is more than likely shot.

[Ajhyman]

Couple things Do you have a new battery in your key remote ? Also try to push Key Fob against push button to see if it starts . Or call 1-800-FTL-HELP Freightliner Gaffney