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Rob-ot · 01-17-2022, 03:42 PM

After the week of single digit temperature in Massachusetts I went out to start my excursion to find a low air light and the engine won’t crank. I have a steady red light on the transmission panel as well. I have checked the relays and fuses and everything seems to be in order. Next I need to see where the engine and transmission coolers are to start checking power to the circuits. Has anybody been through anything similar and could point me in the right direction?

TLDR: need locations for engine and transmission computers.

Mr Lars · 01-17-2022, 04:07 PM

My guess would be a weak battery, that’s why it won’t crank. Recharge, or replace the battery(batteries) first. After it starts, worry about the other issues, they may go away a few minutes after you have the engine running. Cold weather can do funky things to sensors, guages, instrument panels, etc.

Rob-ot · 01-18-2022, 07:55 AM

I’ve load tested the batteries and they’re fine. The chassis batteries are brand new, the house batteries are fully charged as well and topped off with distilled water.

jacwjames · 01-18-2022, 08:04 AM

Low temps and diesel engines don't play good together.

Do you have a block heater, if so activate it and wait for a day.

The engine should also have some sort of grid heaters on the air intake, if temp sensors show low temps the grid heaters will come on but need lots of power while you are cranking. The engine takes more power also due to the cold weather. So even if batteries are up it will be hard to start.

You may also have a battery boost type switch that combines both battery banks. If so use it while you try to start.

Rob-ot · 01-19-2022, 04:50 PM

I’ve tried each of those. My panel has an aux power switch to augment power while starting which I’ve used to no avail. The heater block switch looks unwired - which is infuriating - but it’s not that either. It was warmer today and I still had the same issue as before. I’ve determined this is neither a starter, fuse nor battery issue. I need to find the ECU and TCM to start trouble shooting the wires feeding the pins.

TandW · 01-19-2022, 05:06 PM

Low air. Won't crank. Thought we were going back half a century!

Tha_Rooster · 01-20-2022, 04:12 AM

Quote:

Originally Posted by Rob-ot

I’ve tried each of those. My panel has an aux power switch to augment power while starting which I’ve used to no avail. The heater block switch looks unwired - which is infuriating - but it’s not that either. It was warmer today and I still had the same issue as before. I’ve determined this is neither a starter, fuse nor battery issue. I need to find the ECU and TCM to start trouble shooting the wires feeding the pins.

Has it started for you before?
Sounds like you have just acquired this unit.

Rob-ot · 01-20-2022, 03:59 PM

It was starting and running great up until a week ago. All I need to know is the location of the TCM

wolfe10 · 01-20-2022, 04:07 PM

Low air pressure should have nothing to do with "won't start".

Tell us exactly how far into the start process you get:

With key to ON position, does the Allison shift pad illuminate in "N"? Dash HVAC fan come on? If you have a "wait to start" light, does it illuminate? Voltage when this happens?

When you turn the key to start does the starter click? Turn the engine over at slow or normal speed?

Does the engine try to start?

Are you plugged into shore power? Battery voltage? Block heater on?

We need MORE DETAIL!

Rob-ot · 01-20-2022, 05:21 PM

Correct a “low air” light shouldn’t effect the starting of the engine. The wait to start light comes on - yes.

Shift pad doesn’t illuminate. Just a red light on the mode button which is constantly illuminated. NDNDNRN doesn’t work nor does holding down the mode button for 10 seconds

There is voltage going to the starter and you can hear the engine priming underneath. However, when the key is turned there is nothing. Doesn’t try to start, the batteries are charged, not plugged into shore power. Block heater switch is not wired for some reason but this problem has occurred on the warmer days we’ve had as well.

I’ve tested the relays and fuses and they’re all functioning as expected.

wolfe10 · 01-20-2022, 05:34 PM

Does the dash HVAC fan work with the ignition on.

If both that and the transmission shift pad don't work, suspect either the IGNITION SOLENOID, wiring from the ignition switch or the ignition switch itself.