[mndriver]

been battling this one all winter now. I would set the truck in Sleep mode in these frigid MN temps and it would never shut down.

As I understand it with the carrier reefers, it looks for several things before it will shut down in either mode:

• minimum run time
• >122* F
• Voltage "OK" flag. This is temperature dependent. As the temps go up, the requirement is lower. Like 13.2 volts at 70* and 14.1 volts at -5*F.
• <6.5 amps

I took it in to Carrier in Nov and they replaced the t-stat. When I had it in the shop, ran great. Did everything it was supposed to, till I got it home and parked outside. Still wouldn't shut down. I was seeing 155*F, 13.8 - 13.9 volts and <3 amps charging. But the volts would not give an "OK" flag.


Battery was replaced with an interstate Group 31 last May rated at 950 CCA. It tested out good like 8 times in a row in Feb without recharging when load tested.

I had the glow plugs tested and checked. I ended up having to replace two of them. Not because they were bad, but because the center electrodes twisted out when they were pulled to replace them. We found some bad cracks in the bus bar, so we replaced it with 8 gage wire and connectors. Allows you to replace individual glow plugs without having to take all 4 off and removing the bus bar at the same time.

It will still not start on majorly cold days without a battery boost charger set to 75 amps. It's only showing that it draws 240 amps max and spec is 280-360 amps for starter draw.


Off of the alternator, I was seeing 14.3 volts, at the starter stud, I was seeing 13.85 - 13.89 volts and at the battery I was seeing 13.75-13.8 volts. As the temps go below zero though, I will not see "OK" on the data read-out on the control panel.

I cleaned the battery terminals and the alternator stud as they were corroded and on the starter stud, I simply loosened it and wiggled it. Voltages at the starter went up to 13.9-13.95 and 13.9 at the battery. But it still wasn't quite right.

A call into my carrier guys and that's when I learned about an 80 AMP fuse inside the control box behind the control panel on the road side door. I stopped in to see the carrier guys since I was in town and we looked inside. Yop, the fuse connections were showing high resistance. Enough that the heat shrink on the connector had split from the heat.

Cleaned the connection and suddenly we had 14.1 volts reading at the control panel. Even at 0*F, we were now getting a "OK" signal on the voltage.

I still don't think things are quite right with it as I do have to use a booster to start it even on days like today when it was -5*F and I don't think it's giving an "OK" flag like it should. Once it warms up though, I'll be doing a more thorough cleaning of all the connections.

I highly recommend getting a set of metric micro-gear wrenches for working on a reefer. Makes some places a lot easier to work with. Especially getting onto the starter stud which needs a 12mm wrench. No room for a socket and a wrench will only move about 1/6 of a turn at a time.