Re: Rear a/c is a fan...front is cold
Rear heat and A/C is a hard system to maintain when it ages. If you have the owners manual it should state in there that in order to use the rear A/C, the front A/C must be switched to "MAX A/C", and/or put into recirc mode before the rear A/C will work.
The rear heat, for the most part, it includes an aux. coolant pump, and a rear heater core. If the system (front and rear) have not been properly cared for in terms of scheduled coolant changes and flushes, chances are good that the rear heater core is clogged with rust or other contaminants. The front heater core has larger tubing enabling smaller particles/rust to pass through it, as it's the primary cabin heat source. To save on weight and costs, rear heater cores are generally compact.
The rear A/C operates off of the same compressor, however it has it's own parts in the roof around the B pillar area. The rear A/C line enters (and returns) through the B pillar. If you look under the van on the passenger side behind the front door, you'll notice the A/C lines.
On one of the lines there is a rubber seal. This seal can crack and cause a very slow leak. If you want to know if it's leaking or not, grab your digital camera and make sure the flash is turned on. Take a few photos of the seal, or where the lines enter the B pillar under the van. Look at the photos on your computer/tv (whatever) and if you see bright green, that's the A/C refrigerant.
I found out about this trick when I was trying to diagnose my rear A/C problem on my Durango R/T. Turned out the seal on the line entering the B pillar was shot, and between two shops, they could not heat it enough to remove the seal and replace it. Total cost to replace the line was nearly $3000 (had to remove the roof panel, etc). needless to say I cut off the line and installed a front A/C only line for about $200 with a recharge of the system.
'11 Ram Quad Cab 4x4 SXT 5.7L HEMI (stock); 48,500m
'06 Pontiac G6 GT 3.5L 220hp; 64,000m
'12 Chrysler 200 Limited 3.6L 283hp; 28,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!