I can drive my car from March til October. Last year it became warm and I managed to ignore the problem. But now it is sunny but cold, I am keen to drive the Jag and still have no heating.
I am at a loss what is going on here. So far I have checked the following:
- Pin 67 on the climate control module (on the right side of the center console, behind glove box panel) does not get pulled down. If I pull it down by hand, the relay in the engine bay switches, the pump runs and I do get heat.
- The heated rear window also does not work (it might or might not be coincidence). But it lead me to belive the engine speed signal might not be present. I found out I am not the first one who had that idea (the insulation is stripped on that wire). I checked with an oscilloscope and found correct (3 pulses per engine revolution) on pin 6 of the control module
- I have replaced the climate control module with a used one that was advertised as working (you never know, but unless this is a common fault I find it hard to belive it has the exact same fault as mine). No change in behaivour.
Any ideas what to check next? I am not sure what pin 22 ‘Water Pump Ground’ does? Also, I don’t know what signals to expect on the various sensor inputs. Can the coolant temperature signal on pin 40 cause problems? It is a pulse width modulated signal - what pulse width is a good signal?
All the other sensore should be ignored whent the temperature control is set to “HI”, shouldn’t they?
Help! I am about to bridge pin 67 to ground…
That doesn’t solve the heated rear window problem though. Maybe I should start looking at that problem next to find out if this is related or not. It appears to be related though, not even the light in the switch comes on, and that is the same with a second control panel I have tried…
Cheers,
Harald