500 SEC Ventilation problems

[fisheggs]

Hi All,

1989 500sec with manual controls and temperature wheels for driver and passenger

I have an issue with the ventilation in the car.

With the blower running, the defrost vents below the windscreen are hot and all the rest of the vents are ambient. Adjusting the temp wheel has no effect on vent temperature remains ambient and defrost is hot.

Where do I need to look?


Also AC clutch does not engage and a/c system is full as has just been recharged and in addition to this, the recirculation button does not light up at all.


thanks

 

[neilrr]

Duo valve?

 

[fisheggs]

Duo valve?

Thanks.
Is there any way to test to eliminate?

 

[fisheggs]

Ok

Slight update which has solved it but not.

Fuse 5 was corroded . Replaced it and A/C and recirculation working a treat. BUT there is now no heat lol.

Everything else works fine

Help

 

[Larkone]

Am I right in thinking that the heating controls are vacuum driven? If so then probably a leak or broken diaphragm.