VT vacuum supply to heater tap

[red truck]

Wife's Vt V6 had a problem last year when heater tap would not turn off, due to no vacuum at the diaphragm. Against my better judgment I pulled the dash apart and couldn't find anything wrong. Followed all the hoses, the controls were all working perfectly, operating the little plunger bizzo which supplies vacuum to the hose, which was supplying vacuum as it should all the way to the tap.
Strange I thought, put it all back together knowing in the back of my mind that it would come back to haunt me, and 10 months later...it has!! No vacuum at the heater tap.
I would rather crawl across broken glass face down with my fly open than pull that dash apart again.
I suspect the vacuum hose to the tap is pinched/squashed somewhere under the dash, has anyone ever had this one before?? All the other vacuum operated functions work perfectly.

[accentstencil]

Does the heater tap turn off and on if you operate it by hand at the heater tap? Maybe the tap has seized.

[HARVZ-6]

the heater tap is in the engine bay mate... driver side of engine just below the brake master cylinder

[Zuicider]

ya but the heater tap is ya weakest link they can generally die

[smokin_vx]

+ 1 Replace Heater tap unit about $30.. i did mine when i did the heater core, i replaced the pipes also while i was in there

[red truck]

Heater tap works fine, there is no vacuum getting to it when control turned to cold.
Looks like a visit inside the dash again....

[ronotron]

did you find out what happened?

i have no vaccum at my heater tap too

[sparksy82]

hi i had the same problem and in the end the it was a blocked air line .
try to blow your air lines clear
but make shure you have the air line unpluged on both ends to save braking things
then blow the lines clean with a air compresser
in my case it was it the heater tap metal air pipe
so i just replased the heater tap