Okay, the vehicle is a 1988 E250 ClubWagon 7.3 IDI diesel with front and rear AC/heat. I have 3 questions for you:

1. I found that the rear heater core is getting coolant flow constantly which is making my rear AC blow 75* air. These models don't have a blend door in the back, they appear to have a valve that is only allows coolant flow to the rear heater core when the heat is turned on. Problem is that I can't seem to find where this valve is located on the van or what it is called to locate it at a parts store. Does anyone know where on my van this valve is located?

2. My rear blower only functions on High. I know there is a resistor set up in the rear that controls the blower speed. Before I just replace this, is there a way that I can test it? That way I am not just throwing a $25 part at it and hoping.

3. Is it possible that the Resistor setup for the rear fan speed would also be causing the rear coolant flow valve to not work? I know it's a long shot, but does the valve signal flow through it when the AC is on to tell the coolant valve to shut?

Thanks

 

Fixed!!!! Pulled the doghouse, tracked the lines and found the valve that diverted the hot coolant during the AC operation. It was rusty and wasn't moving. Called round and found that the local AZ had one in stock. Got the new one installed and it appeared to be opening and closing correctly. Re installed the doghouse, cranked up the A/C and started testing temps. At idle I had been getting about 68* out of the rear unit and 58* out of the front. Now I was at 58* from the rear and 56* from the front at idle. Went for a drive around town. About 35mpg stop and go.....54* out of the rear unit and 52* from the front. Jumped on the highway for a cruise at 65mph. 48* from the rear unit and 45* from the front. Then just to make sure the valve was working I switched it to heat. Within a minute I had 130* air blowing out the front and rear vents. Switched it back to AC and got the same cold temperature results within minutes.

I was also having an issue with the rear blower. It only worked on high speed. Any other setting and fan didn't even move. AZ had 2 blower resistors in stock, but they both were listed for only the front blower. The one they had listed for the rear was discontinued and could not be ordered. From the pictures it looked like one of the ones they had listed for the front was identical to the back unit. Examined it further when I reached the store and decided for $25 I would give it a shot. Installed perfectly and works like a charm....I now have low, medium and high fan speeds.

Overall a successful afternoon wrenching on the van.

 

Glad to hear this all came together so relatively easy for you Jayro!

'Tis a good day when things work out just as we plan (or hope)!