Strange issue with climate control
 

Hi all,

I'm convinced that there is an electrical problem with the climate control on my ZT as I'm experiencing the following issues:

1. Passenger temperatures on the display don't stay within the 5 degrees of the drivers side anymore. I'm sure it used to increase the passenger side temp if you the drivers side was increased. It allows you to select Hi on one side and Lo on the other.
2. I get ambient temperatures at all temperature ranges between 16 and 28, yet if i choose hi, then boiling hot air is pumped out at foot level.
3. Despite a recent regas, cold air conditioned air doesn't come out when you select lo. However after disconnecting and reconnecting the atc panel wiring, it blew freezing cold air for 5 seconds before reverting to ambient temperatures.
4. Whatever temperature selected, the passenger side seems to be a higher temperature than the drivers side.

Does anyone know what is going on with it?!

Many thanks in advance

Have you run the ATC Diagnostic checks?

Press and hold both the AUTO and the air distribution buttons and then turn the ignition key from 0 to II. The climate control screen then cycles on and off while the checks are run. On completion, the display will show "FC" on the passenger side and a two-digit code on the driver's side. Codes are:

00 - No fault found.
11 - In-car temperature sensor open or short circuit 25C/77F.
12 - K bus fault with ambient temperature input 10C/52F.
13 - Evaporator sensor open or short circuit 5C/41F.
14 - Heater coolant temperature sensor open or short circuit 70C/158F.
21 - Sunlight sensor (left) open or short circuit no solar heating correction.
22 - sunlight sensor (right) open or short circuit no solar heating correction.
31 - LH temp servo motor open, or short circuit, motor or flap mechanism seized, servo motor locked in position.
32 - RH temp servo motor open, or short circuit, motor or flap mechanism seized, servo motor locked in position.
33 - Distribution servo motor open or short circuit, motor or flap mechanism sezed, servo motor locked in position.

With acknowledgements to Mike, from whom I obtained this information over 5 years ago (it's probably still on here somewhere but I don't know where).

Just checked the diagnostics test and its showing error codes 21 and 22. Is there an easy fix for this?

error codes 21 & 22 will always be present unless you are in strong sunlight, nothing unusual there :)
Altering the drivers side will not alter the passenger side and vice versa, the displays are totally independent IIRC

I may be wrong, but I thought when "Lo" is selected, it doesn't use the aircon anyway?

I'm fairly sure LO does use the aircon, but I too may be wrong.

Probably does to be honest, I think I am incorrect with that statement, I've most likely misread a previous post on here regarding it ;)

Maximum difference between driver/passenger temperatures is 5 degrees

I've been able to manually engage aircon using lo before, and even on 16 deg it should be cooling the air. I can't explain why i got 5 seconds of ice cold air after reconnecting, but it leads me to believe that the temperature control system in some way at fault.

I'm sure the unit used to prevent differences greater than 5 degrees from being selected, can anyone confirm this?

I thought it did, but I have just tried mine and it doesn't. I ran the driver's side control all the way from LO to HI and back again and the passenger side display remained at its normal setting.