E350 AC issue with Starcool question(s)

[JoeH-SMB]

Hi All,

After replacing the compressor, accumulator, and orifice tubes the rear Starcool AC rear blows cold (42F) but the front is only 68F. My diesel mechanic has replaced the condenser twice and the manifold-T junction that ties the two systems together has been checked and is free-flowing.

Both systems were flushed and with a full charge the low side pressure is38-48psi and the high side 250-310 psi. Specs check out and the pressures are good.

The only red flag that can be found is that the evaporator isn't getting cold. Any ideas that might help? Is the orifice tube on the front factory OE? On the rear it's a variable orifice tube but not sure if that's the right one either.

The fact that the accumulator isn't getting cold would appear to rule out a blend door issue. There's a solenoid that was added to the front but that only operates on 110 and is functioning. Any ideas or anyone run into the same issue?

 

[JoeH-SMB]

This is the lead I'm chasing now from an older thread:

I have seen times when a Factory Ford fuse that is supposed to provide 12 volt "ignition on" power to the Starcool Relay Plate is bad, thereby allowing the Starcool Solenoid Valve to close whenever the Thermostat is set to "cool". If this happens, you will have no refrigerant going to the dash Evaporator and will not get any cooling out of the dash vents, but you will get cooling out of the Starcool Evaporator.

The question is, where is this fuse located?* I'm not sure if it's OEM or is a fuse added later since it's for the starcool solenoid or if it applies to when the engine is running or instead is connected to shore-power.

 

[Scalf77]

Typically SMB would get their ignition signal in the steering column and add the fuse there.

Typically a blue wire going to terminal #2 of Starcool relay.

Yes, if you were not getting the engine run, it would think it was running off of shore power. If that is the case, do don't turn on your inverter.
Some other documents to help.

Starcool service and operating manual

Starcool Flowchart

 

[JoeH-SMB]

Thanks Scalf77, this is very helpful! We'll chase this down tomorrow.

 

[JoeH-SMB]

Just to follow up, got it working but not exactly sure what did the trick. It might have been something as simple as a connection. Went through and pulled all of them and checked all wiring. System is now operating normally. I'm going to replace the cheapo thermostat in the rear just for peace of mind.

Thanks again Scalf77 for the helpful links!