My wife has a 1995 Ford Fairmont, which she loves, and it is still going really well. But the heating side of the climate control does not seem to work anymore with only cold air being blown out regardless of how high you put the temperature setting. I have pulled all the dash out as far as I dare, but could not get access to the heater box to check it. The climate control shows no errors when I run the module self-test. The water pipes up to the tap under the bonnet are warm; the tap seems to operate on and off. I'm not sure where I go from here.
The control for the heater/air-conditioning system in those model Falcons is notoriously unreliable. I would be looking there to find the fault, it probably needs replacing.