Ambient Air temperature

[rosemary]

Hello Folks .
Well the saga continues, MOT booked for 30th May and I expect a failure due to a suspension clonk somewhere on the nearside front which I can't find lying on my back with a jemmy under the car. I've replaced the rear stabiliser bars and ant-roll links (parts £107). Job for the Village Garage on their four poster. Not too worried about the cost a few hundred I expect but I've already spent more than the value of the car to keep it anyway. I'm a nut. So I thought I'd have a look at the ambient temperature sensor instead. I read all the Forum posts beforehand. Today it was 23 deg, the ambient air temperature on the panel was showing 10 deg ??. I bought a secondhand replacement for £12.69p and fitted that. Still showing 10 deg. I connected my OBD reader and it told me the ambient air sensor was shorted to ground. Oh. I fitted the original back and consulted the reader. No DTC's but still 10 deg. I fitted the one I'd just bought again and it now showed open circuit on the reader? and 10 deg. Does anyone know how or if the panel is configured to show 10 deg as a default reading.
I have now ordered a new sensor from SNG Barratt at £30 ouch! assuming that it is tested to work and reflect a true temperature. We'll see what happens. Note replacing the sensor is easy through the lower grill space. the locating plastic rivet allows the plug/sensor assembly to be slid off for sensor removal from the harness plug.
Dave

[rosemary]

Hello Folks
New sensor arrived lunchtime. Before fitting I checked temperature on panel, 10 deg. Fitted new sensor, 10 deg. Removed sensor, 10 deg.
OBD reader showed open circuit. Has anybody any ideas.
Dave

[andypryce]

Hi Dave,

I assume you have done a hard reset by removing battery and leaving disconnected several hours? If so, then no other suggestions to make, seems odd...

[JimboV8]

You need to take some continuity readings of that particular wiring loom to the sensor. You may well have a broken wire within the loom to the sensor.

[Montana5]

Dave, have you tried blowing hot air over the Sensor, or I recall someone saying his worked only after he took the Car for a Drive.

Doug.

[rosemary]

Hello Folks
Thanks for the responses, I haven't done a "hard reset" one of Mike Kennedy's tricks, I have checked the continuity of the wires confirmed by my iSoft930 OBD reader, don't know what I'd do without that now.
I spent most of yesterday evening reading all sorts of Forums and came across a contributor who said in summery:- "after sending several sensors back to suppliers as faulty on Rover 75's and Ford's I discovered that you had to drive the cars around until it was up to temperature, the ambient temperature sensor then began to deliver sensible readings". I thought this odd to say the least however this morning I tried it out and loo and behold the temperature on the panel came to life and delivered the correct ambient temperature this morning. So I'm not touching anything else and going for the MOT.
Dave

[rosemary]

Hello Folks
Well surprise surprise the car passed the MOT with no advisories, first time in years it's gone straight through with no problems. Now to Tax it and back on the road for June. I wonder what's next, really strange having rear sensors after all this time.
Dave

[BrizzleJag]

I have the same problem Dave mine shows 10 degrees. I assume it is located towards the bottom of the grille? What do you need to remove to access it?

[rosemary]

Hello Brizlejag
You don't need to remove anything. Looking at the front of the car just to the left of the number plate.the lower grill opening, it's in there. You can get your hand in to the sensor and socket. This assembly is held in place on a plastic rivet affair, the assembly is slid and clicked on to this rivet. Lever it off (it's clicked in place) and you can unplug the sensor from it's socket. Note it also has a locking tab between it and the socket. The sensor part looks a bit like a spark plug. SNG Barratt sell new ones but it is a Ford Component and I bet it's cheaper from a Ford Dealer.
Mine now works after driving the car about a bit I don't understand why.
Dave

[BrizzleJag]

Thanks for the information Dave, great help.

[BrizzleJag]

All done and fitted, part No XR858222 £30.96 inc VAT from Moss Europe (they are doing a fair amount of Jag parts now). As Dave said located in the upper part of the lower grille just about level with left edge of the number plate looking from the front. You need to get on the floor with your head pointing skywards to see it. I have added a picture but it's very difficult to see even using the camera on the phone, that's why it's not a great picture, but you can just make out the white lead coming out. Pull the senor away from the body of the car taking care not to pull the wires out, the carrier attaches with two small round push fit clips/rivets. Unplugging the sensor from the carrier is a bit fiddly, once out push in the new sensor in and reattach the carrier with the little plastic rivets locating into two holes. As soon as I turned on the ignition, Bingo! it started reading 19 degrees, a quick spin around the block and it dropped down to 17 degrees so it looks like it's working fine.

[Powerband]

Greetings. I have a similar problem to this except my temp is reading -17 regardless then after 5 minutes driving it returns to the real temp. But at this point the climate control doesn't work properly still I can either have very cold or warm to hot there is no cool at all. so if I switch it from low to 17 it goes warm not cool...hope that makes sense.
Anyway not sure I've no doubt everybody uses this place but if not it maybe of help www.jaguarclassicparts.com . The ambient sensor is about £27 including vat and they are a part of JLR so in theory genuine parts. I use them because they are very close to me and I can have the stuff sent to the local jag dealer and check it before I pay any money. The people there are also very knowledgeable and incredibly helpful.

[SteveKK]

You might want to check out this website as there have a lot of detail about the climate control system in the S Type.

http://jaguarclimatecontrol.com/

If I ever get my car into a roadworthy state I'll be following their diagnosis on my system as I've had it repaired before at great expense.

Regards,
Steve

[BrizzleJag]

Greetings. I have a similar problem to this except my temp is reading -17 regardless then after 5 minutes driving it returns to the real temp. But at this point the climate control doesn't work properly still I can either have very cold or warm to hot there is no cool at all. so if I switch it from low to 17 it goes warm not cool...hope that makes sense.
Anyway not sure I've no doubt everybody uses this place but if not it maybe of help www.jaguarclassicparts.com . The ambient sensor is about £27 including vat and they are a part of JLR so in theory genuine parts. I use them because they are very close to me and I can have the stuff sent to the local jag dealer and check it before I pay any money. The people there are also very knowledgeable and incredibly helpful.

I think it's unlikely that this is the problem with your climate control issue. The climate control on my car continued to work perfectly even when my ambient air temperature sensor was faulty.

[chris1c1]

The ambient air temperature sensor has two jobs, 1. it gives you the outside temperature on your centre console (you are aware that) 2. it stops the air conditioning if the ambient temperature drops below 0 degrees C. A faulty sensor may do the same thing. The sensor is a PT100 device so at 0 degrees C the resistance measured with an ohmmeter will be 100 ohms, at 100 degrees C it will be 138.5 ohms. Take the sensor out and measure the resistance. Replace a faulty sensor with one from Ford, it is a Ford part, a new one will cost about £5.00. Hope this helps.