Hello, I've recently purchased a 2005 (05 plate) Supercharged (4.2) L322 after owning a Sport (L320) for a number of years and have been working through a few issues with it. I've got one issue which has me stumped and I would like to ask for some advice.

I noticed a few days ago that my feet were cold and all the hot air was blowing through the vents in the dashboard that point towards your face (with the climate control set to auto). I tried using the manual buttons to select the foot vent output, or the screen output. This seemed to marginally reduce the amount of air coming out the face vents, but no air came into the foot well or onto the screen.

Temperature control and air conditioning works well but the output control just doesn't seem to work, which is an issue on cold mornings and especially with only a portion of the heated screen working (a project for another day).

I connected my slightly dodgy copy of IDS (see attached picture) which shows a whole number of errors relating to line interruptions on the stepper motors which control the direction of the air. These are shown as active. Sadly when I click on the troubleshooting procedure I get an error message (so this is clearly where a cheap eBay copy of IDS falls over).

Please can anyone help with advice on the next stage of diagnosing the cause of this issue. As it is reporting every motor has a fault I assume this is either a controller, wiring or fuse issue rather than the motors themselves failing but I don't know where these are to start investigating further or if there is a common fault. I couldn't find anything with Google.

I'd begin with checking connections and/or replacing the air quality sensor which is located on the radiator fan shroud. Most accessible of the probable culprits and not too costly at less than 50 quid...

Thanks. I've checked the wiring to that sensor and it looked it good condition and was securely plugged in. Checking with a multimeter shows 5V on two of the wire going to the sensor so I am assuming the rest of it is also in tact.

I have therefore ordered a new sensor as suggested and will update you once I receive it to see if it has made any difference.

Fingers crossed...

To update this thread in case anyone else has the same issue I tried replacing the ambient air quality sensor (part number JTF100130 £51 direct from Land Rover Classic Parts). This cleared the fault code regarding the air quality sensor but didn't solve the issue regarding vent operation.

I then ordered an ATC ECU (the main heater control panel on the dashboard) off of eBay as for the sake of £20 it seemed worth trying. When I removed the original panel from the dashboard I found that the M Bus connector (which controls the motors) was not connected. Reconnecting this connector (to the original control panel) solved the issue. It is a small black connector with a Grey, Grey/White and White wire. It was not immediately obvious where on the ATC ECU it plugs in but I found it after a couple of minutes looking.

I've got a couple of other electrical gremlins I'm still working through (I'll start another thread on these if I need to) but at least this one was an easy fix in the end. I've just got to hope it wasn't deliberately unplugged due to a battery drain or similar but I'll see how it goes.