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My first post here on this great Forum,
Looking under the car today fitting the replacement Bumper Under Tray I saw this hanging down under the Front Left side of the motor (97 XK8 Conv). It is attached to the main engine wiring harness at the front of the suspension tower. It is attached by a connector with around 2-3 inches of loom attached. Looking under the car and from above I cant see where this belongs or what function it does. However I do know that it belongs somewhere and would like to replace it back where it belongs. Obviously the two bolts holding it in place are long gone. I am sure some oracle of knowledge on this site will be able to identify it and set me straight.
Last edited by GGG; Nov 10, 2022 at 05:55 AM.
Reason: Add 'RESOLVED' to thread title
I suspect that is the compressor lock sensor. Someone replaced the A/C compressor with a unit for a later car (that sensor was deleted from 98 on), and left it connected to try to keep the climate control electronics happy.
That solves the mystery then.
I will fasten it up and add that to memory.
I have no fault codes so it seems to be doing its job of fooling the module.
Thank you.
Michael H,
I can confirm your diagnosis on the fitting of a replacement AC compressor.
New compressor and hoses looks to be done in 2021 going by the Gas refill decal.
Good call Sir.
The AC is in fine operating order.
I live in a Sub Tropical region and it handles the humidity and heat well.
The car is Anthracite with a black Top and Black interior so it does get a work out.
Close on 30C today.
I have a AE900I, (advanced software) Diagnostic tool and, no codes displayed.
I feel the mechanic who left this item in place may have identified problems and provided the solution simply by leaving it connected fooling the system as you commented on correctly..
Smart thinking.
Odd.
Service Training Course No. 701 states on page 30: "
Because the power steering pump and air conditioning compressor are driven by the same belt on the V12 and the AJV8, a compressor lock
sensor is installed to provide the A/CCM with an input to verify correct operation. The compressor lock sensor, similar to an ABS wheel speed
sensor, provides a pulsed signal indicating compressor pulley speed. The A/CCM compares the pulley speed to the engine speed input received
from the ECM.
If the pulley speed indicates belt slippage, the A/CCM cancels the A/C request to the ECM to protect against drive belt failure.
The A/CCM also flashes the control panel A/C switch LED as an immediate warning and flags DTC B1862.
The compressor lock sensor is deleted on AJV8 applications after the 1997 MY.
"
So in theory, it shouldn't work - hence my question. I wonder if the clutch wiring has been modified?
"In theory, theory and practice are the same. In practice, they are not. (A. Einstein)
Then I got sidetracked reading about bumble bee aerodynamics...
Thanks for todays homework,
It is very hard to confirm if the wiring has been modified.
From what I can observe the wiring loom in general appears to be standard. Unsure of the Connectors at the AC clutch, they are out of sight.
Took the car out for a 60k run today. Using the AC in different settings all seems to be working well.
On return home and checking all modules there are no codes to report.
No LED flashing, nothing at all to indicate there is any cause and effect by the AC pump replacement, including the sensor delete from the role it is designed to do.
Question, with the delete of this sensor in the 98 XK, why could the same delete not be applied to the 97 MY when a Compressor is replaced?
What were the changes for 98?
Finding a detailed AC wiring diagram for the 97 model has not been successful.
Think I may have to go along with that Bert Einstien Chap, he may be onto something in this instance.
Hi,
If it's all running OK I wouldn't agonise over it for too long
The 97 climate control module was superseded for the 98 MY, so I imagine that if the original were to be replaced on a 97, it wouldn't need the lock feedback anyway.
Thanks Michael,
I have stored the link you have provided for the wiring diagram.
I shall be curious and see if the CM has been replaced with a later version.
However, I will as suggested, leave it as is and be happy with the cold AC output.
Thank you for your comments you are very knowledgeable on the XK.
Now all I have to do is remove the Leeper from the front of the bonnet/hood and, a plethora of other work that makes up my list.
This is my 15th Jaguar.
I must be a slow learner.
What is this? - RESOLVED
