Hi All,

I'm finally getting round to trying to diagnose why my center dashboard vent never opens.
Does anyone know if there is any sort of mechanical linkage between the windscreen defrost vent mechanisms & the center dash vent mechanism, or can they operate independently?

I've been testing the 2 vacuum solenoids behind the right hand side lower vent panel.
- the center vent (black tube) one is definitely working - it switches vacuum on when heater is on max cool, & off when heat turned up. Center vent doesn't open though.
- the defrost (green tube) one doesn't appear to do anything, but maybe I haven't tested it fully yet. I'm not sure under what circumstances it should activate. I tried crossing them over & connecting the center vent solenoid to the green vac tube for the defrost vents and it did close them off when under vacuum so the defrost actuator/physical side of the defrost mechanism does at least appear to be working.

I'm just trying to work out if my center vent apparently being stuck is linked to the potential defrost solenoid issues, or if I just need to somehow physically force the flap open/unstick it to get it working.

 

The centre vent is vacuum operated. It only opens when cooling is called for and it takes a while to stabilize and open the vent. If the car is parked in the sun on a hot day and then you start it and turn the AC on it should open the vent after a min or so. It won't be instant.

 

The center vent linkage is interconnected with the defroster vent linkage. If the defrost vent will not close, the center vent cannot open. So you need to fix your defrost vent issue.

Jon

 

Hello,
I have the same problem, the defroster does not close.
Did you manage to find the problem?

 

The vents have strip of foam rubber around edge to help seal, time turns these strips to a sticky mess which is quite capable of holding the vents closed.
Check this is not the case on your car.

 

I believe my 83 is Delanair 2, but the center dash vent does not open until the inside temperature gets near the set temperature on the temperature knob. I suspect this is normal.