Air Con Problem

Hi Guys,

Last week I noticed that when pressing the Ext button on the air con display I was getting whacky readings. One day it decided it was -30c outside, the next day 20c as so on. The effect is that on some days when you want a bit of cold air, say when its 15c outside, and the air con thinks its -30c, you can't get the air you want.

Anyway, I ran the self diagnostic on the air con panel and it came up with no faults, so I decided to try my luck and replace the ambient air temp sensor which is located behind the front grill. my assumption was that the faulty readings could be a busted sensor. (Part Number 077500-4220)

Anyway, I don't seem to be able to remove the existing sensor? Anyone got any tips. Also, anyone experienced a similar problem with the whacky ext temp readings on the air con panel and come up with a different fix?

Thanks Guys.

i may be wrong but doesnt it use an temperature reading from inside the car to decide whether to put out hot or cold air

Paul...you could be right, although I don't think there's a temp sensor inside the car?
Any ideas what could be causing the wacky readings and any idea of a fix?
Cheers

Mendez said:

Paul...you could be right, although I don't think there's a temp sensor inside the car?
Any ideas what could be causing the wacky readings and any idea of a fix?
Cheers

Click to expand...

there is one behind the little grill next to the electric mirror buttons

the ext. temp readings are coming from the outer(ambient air temp.) sensor (nr.5) the inside air sensor is the one with small ventilator near the steering wheel(see attachment) ... the ambient air temp sensor is covered by self diagnostic only for open or short circuit but as you describe the fault it might just have some internal failure... that's what i would do too as first repair...it's holded by a bracket, just remove it from there

Vanmancan said:

there is one behind the little grill next to the electric mirror buttons

Click to expand...

thats what operates the climate control
the temp sensor is out behind the grill

Thanks Chaps....I was pulling at the sensor trying to remove it and it just wouldn't budge, so I'll give it another go.
Cheers.

It won't take a minute to check the internal one for dust with a torch through the grill and just use a vaccum to suck it out. Mine was filthy and I can now see the sensor (looks like a small halogen bulb)
Griff

Nice one thanks

Hi Guys...no luck with this! the new Ambient Sensor arrived and I replaced but the outside temp reading on the Air Con Panel still says -30c?

Any ideas on next step?
Thanks...Tom

1. first check for earth in the sensor's plug (black/white wire), if good

2. continuity check on the wiring from the unit to the sensor, see RAVE -Electrical library - connector views, locate and unplug C0067 , put ohmeter between pins 6 - 7 and bridge the pins in the sensor's plug...you must get closed circuit with the bridge, if you have continuity check between C0229 -6 and C0792-6 the continuity of that yellow/green wire

3. make sure the plug at the unit's back makes good contact after that

if all these things are ok it means its a unit(aircon ECU) internal fault

i hope you didnt buy a second hand sensor though

Thanks Sierra....no brand new original Landrover Sensor from Rimmerbros.

Cheers...Tom

Hi Guys just an update on this.

Took it to a local mechanic and he traced to the problem to corroded wiring at the front of the disco just behind the grill. Wiring replaced now and sensor working fine, so all is well.