Tuesday afternoon, I found out why replacing the climate panel on my 1990 Jaguar Sovereign had not solved the problem. It was the Climate ECU module. I sourced a good used one from eBay for $85 and installed with little difficulty. That’s a bit misleading as I had already removed the glove box several months earlier. But with that out of the way, it really was a simple piece to remove and install.
After so many disappointments, I chose to pray before turning the key. Thankfully, the climate panel worked this time. Instead of all the lights being lit all the time, they now light up only when told to. I can also hear the flap move depending on what location is selected.
Right now I am leaving the fan selector on defrost for two reasons. First, neither of the heater blowers are currently working. The used unit installed last year had slowly been dying and finally stopped working in time for winter. Second, even without the fans working, heat rises. So, with the selector on defrost, I don’t have to use the portable heater. That, along with the makeshift-portable fan blower, has allowed me to drive to and from work without steamed up windows.
Next step: Rebuild one or both of the fans.