After the better part of a week of work I just finished putting my car back together. Now in all truth I was in no hurry and did some modifications along the way but still removing the dash top and pulling out the right blower unit is no walk in the park. There are a LOT of parts to remove and electrical connectors to (carefully) disconnect. It doesn’t help that Jaguar decided to use a different size screw or nut on almost every fitting !
I started this job because my right blower unit would only operate on high and demist. Sure enough it turned out to be the infamous Darlington transistor and when I replaced it everything worked perfectly again. Because the fan assembly circuit board looked great (very clean with no corrosion) I decided to just stop there even though I purchased all the other resistors and diodes. “Leave well enough alone” or “First do no harm” … you take your pick.
As far as the modifications…
I removed both demister door flap assemblies and reinforced them with long metal rods secured with epoxy. Hopefully this will keep them from cracking in the future, a common failure.
Previously I had removed the vacuum operated actuator on both fan assemblies that controls the fresh air/recirculation doors and permanently fixed the doors to the recirculate position.
I completely removed the center vent vacuum actuator and door along with the large plastic baffle that they attach to. This resulted in much greater overall airflow.
The airflow out of the facia side vents has always been anemic at best, more like nonexistent. To increase the flow to the vents I fabricated some metal duct work which redirects the air. This resulted in excellent airflow out of both the center and side vents.
The picture shows the bottom of the dash top as if you were looking up from the evaporator, but If you’ve never had your dash top off it probably makes no sense to you at all.