For the second time recently the climate control on my '89 XJS V12 starting blowing air into the cabin while the switch was firmly in the 'off' position. Fiddling with the controls while this was happening had no effect. On both occasions it only lasted a few seconds; the first time I just shrugged it off, but now I'm thinking there might be a problem that needs investigating. My A/C refrigerant needs recharging, but otherwise the system seems to work normally except for these two recent incidents. Has anybody had a similar issue? Very grateful for any replies - many thanks, Andy.

 

I *suspect* the entire climate control system isn't coming on but, rather, just one of the fans.

If that's the case you probably have a problem with the circuit boards. They're mounted in the fan boxes and subject to moisture related oddities....most commonly, but not exclusively, coming on and not turning off. Ever.

There's a Darlington transitor, a relay, and a couple diodes on each circuit board. Good DIY project to rebuild them but removing the fans is pure misery. I'll try to find some pics for you.

Cheers
DD

 

Air conditioning blower control



Cheers
DD