the people a/c is working fine...blowing cold....and the line to the battery cooling coil is ice cold under the back first thing in the morning....seems like when it starts getting hot outside, the line under the back just stops recieving freon....i know there isn't a valve between where it hooks under the hood and where it goes to the back...so this isn't making since....anyone know if there is an expansion valve in the line going to the back? maybe when the pressure gets high(when its hot) the valve shuts off.....as long as its not hot outside, and the line in the back is getting ice cold, the bt continues to fall...but when its not getting cold the bt gradually rises until the computer tells the battery assist to quit...i really appreciate all the replies...maybe we can get this figured out soon...i really don't want to take it to the stealer and have them tell me what i already know

 

just went back out there and did some more checking....bt 44....started it, left the front a/c off....engine stayed running...a/c compressor not running...went to the back and i can hear the fan running to cool the battery...took filter out to see if it was using outside air or a/c air and the flap was closed like it is supposed to be using the a/c to cool it not outside air....let it run for awhile and it never did cool down...i assume it didn't because the a/c wasn't running

 

OK, so you know the A/C System itself works fine, so the next thing is verify the rear coil that feeds the battery. It could be the coil and supporting stuff, it could be blocked ducting feeding cold air to the battery, or it could be a faulty fan (as I recall there is separate fan in each battery pack).

The easiest may be to first run the ducting and ensure it is clear, the next may be the the fans, and finally the A/C stuff itself. There may be a TXV problem or there may be a sensor problem that tells the A/C to turn on when battery temp goes up.

Good luck

 

i see your point but if this "system" is like a dual a/c system on a regular suburban/expedition(which it basically is as far as hard parts) the coil itself should be cold anytime i run the front a/c......it is cold as long as its not hot outside...when it gets hot outside, the rear coil stops getting cold....everything first thing in the morning...i really wouldn't mind taking it to the dealer if there was a dealer around here that was well versed on hybrids..keep the ideas coming

 

the fans are working back there...i can hear them and when i pulled the cover off i can hear/feel it....but its just feeding hot air to the batterys because the coil is not cold...if i can figure out why the coil back there is not cold, i think my problem will be solved.....i've had plenty of rigs with dual a/c...if this one is like them, it acts like its under charged or over charged....

 

If I get it right then the system seems to work fine in cooler weather but shuts down when the temp goes above a certain point.

I've known some wiring to open up in hotter temps. Probably a long shot but go thru and disconnect & check connectors. You'll likely see little of note but the reconnection should clean them up. My best guess is that some corrosion gets into the connector blades and when temps go up so does resistance (Note that normal thermistors have a temp-resistance curve that decreases with increasing temps).

It sounds like the issue is the control circuits. Check out the thermistor that provides the signal telling the TXV to function.

You said the fans were working: did you verify adequate air flow? A piece of paper or a leaf in the wrong place can wreak havoc.

 

where is this "thrermistor" on the FEH? as far as air flow, i did have a air flow problem caused by leaves,feathers,grass,etc...i already took it to the radiator shop when i first got it and they cleaned all the junk out of the rad,condensor,etc...seems to me the one thing that is causing it to stop working is the loss of flow of refrigerant to the rear coil...would be nice if i could somehow stop the flow to the front coil and see what happens then(it would have to go to the back coil then) i'm probably gonna either drain or add some refrigerant to it and see what happens

 

if i was still loosing flow in the condensor/rad. then it should try to go back to normal when traveling at high speeds forcing air across the condensor...i really don't think its that....i wouldn't think the compressor is bad because its still cooling?

 

I'll have to look it up in the shop manual. It may not be serviceable separately.

When I spoke of air flow I meant in the battery not up front.

If you're not losing freon out of the system the fault may be the TXV or the circuitry that controls it.

 

Thermistor- if you have the shop manuals you can find it on the electricla diagram locators. Its it the ducting, separate from the battery, up the drivers side wall of the rear cargo area.

You'll have to look it up from here. Might be that just disconnecting the plug & reconnecting it might help (Long shot but sometimes works).