Disco 2 - AC codes 21/22
 

I tested a recently purchased truck and my AC codes are 21/22. How do I replace the Sun sensors?
Will the AC function without it. I tried lowering the temp to LO and still could not get the snow flake. It is cold outside and was hoping its just EXT temp not letting the AC run.

I posted this on another LR forum so hopefully this will help you...

“I searched the forum to see if I can piggy back on someone else's Disco II posts about air conditioner fault codes. I couldn't find any so I'm posting here for future reference to help others.

I completed the air con diagnostics check on my 2001 Disco SE by following these steps from this video

Land Rover Discovery II A/C Diagnostics

:

1 - Turn ignition OFF.
2 - On the climate control panel, press and hold both AUTO and Air Distribution buttons.
3 - While holding these buttons down, switch ignition ON to position 2.
4 - Keep holding the buttons for 4-5 beeps and let go. The fault code (FC) results will be shown on the right side of the screen.

After doing this check I had two fault codes that popped up on the screen; 21 & 22.
I did a Google search and found a list of the fault code descriptions:

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
*22 - right sunlight sensor fault - open or shorted
31 - left servo motor
32 - right servo motor
33 - distribution servo motor

I did another Google search about the 21 & 22 errors and found the answer on an Australian LR forum. Someone stated that you will get fault codes 21 & 22 if you don't do the test in direct sunlight. It made sense since I did the diagnostics check in darkness of my garage.
After reading this, I pulled my Disco out of the garage, let it sit in the Georgia sun for an hour, redid the check and BAM! I got the no fault code of 00!

I hope this helps others! Cheers!”

AC - should there be a snow flake?
 

So the code cleared doing the test in the sun. I still don’t hear the AC clutch engaging nor do I see a snow flake on the display.

i don't think there is a snowflake to show.
have you tried turning on the windscreen defroster? that should force the a/c to come on since it acts as a dehumidifier.

Tried the defrost and still warm air

21 & 22 come up if you do not do the test in direct sunlight. In other words, pull the truck out of the garage on a sunny day and rerun the test

if the ac is not working, see if the system needs to be charged