Ok, here's a challenge for the Disco Gurus:
I bought an '03 Disco HSE in March last year. Currently has 163000 miles. Overall good shape, except for the AC. Last summer the AC wasn't giving consistent cold air. Some days it was good, some marginal, some started good, then warmed up, others started marginally cool, then went cold. I recharged the system. It seemed to help, but still fluctuated, even on LO. As the temps started to drop in the fall, it maintained a comfortable temp. When the outside temp dropped below 30, it started to fluctuate again. Coolant level was good, AC pressure was good. Through most of the winter, the air was not very hot even though I had the temp set to HI, sometimes it blew cool air when the outside temp was 15. Through all of this, the engine temp gauge was consistently right in the middle. Sometimes I would shut the system off for a few miles, then turn it back on and it would get hot for 10(?) minutes, then cool off again. Sometimes when I'm cruising at 70mph and back off, the temp warms up for a while.
Now that its getting warmer, its seems the air temp is more stable and it responds to temp settings when I change the climate control.

Are sensors a problem? Does the climate control unit get wacky over time?

Any help is greatly appreciated.

Thanks!

 

On my 2001, I found that the auto control is crap, could be it has worn out. Same issues you described. When I switched to econ and manually control the temps things got significantly better.

 

I've never had any issues with mine, so I don't know how helpful the diagnostics function is but worth a try if you have not already.

 

Honestly if your heat output is weak I’d check the heater core. With a good flowing core both in/out lines will feel nearly identical. If one is cold & one is hot = your core is clogged. Very easy to flush. Cut off the original lines vs damage the heater core metal lines (then simply replace with 5/8 heater hose cut to length). First flush out the core backwards, then when it flows good flush it the other direction. Re-attach the heater core lines & top off the fluid (shouldn’t have to add much at all).

Now your heater output should be perfect!

P.S. for max heater output ECON must be enabled (AC off aka vent mode). Modern cars will usually use the AC all the time to keep stuff from fogging up, but for 100% max heat output ECON must be enabled on a D2.

 

00 - no faults
11 - in car temp sensor fault
12 - ambient sensor fault
13 - thermistor fault
14 - heater coolant sensor fault
*21 - left sunlight sensor fault - open or shorted (need to run test in direct sunlight)
*22 - right sunlight sensor fault - open or shorted (need to run test in direct sunlight)
31 - left servo motor
32 - right servo motor
33 - distribution servo motor