wk caprice climate control issue

[Jacob1991]

with the climate control on in my wk caprice. with the fan on any setting and air on the main face vents ive found that sometimes the air will reroute to the windscreen. Ive also noticed it only happens when driving up a hill in top gear (auto). The issue usually clears once the car isnt climbing the hill or if i bring it back to 3rd gear. Makes me think its a vacuum issue as im sure the climate control units rely on vacuum from the engine. Any ideas?

 

[Greasy Hands]

100% sounds like a vacuum leak to me, either insufficient vacuum for the system as a whole, a failed check valve or there is a vacuum pod with a torn/cracked diaphragm.

 

[Torquative]

yeah theres a number of threads on this issue - its common across the VY range and into the VZ range.

This topic probably has the best info throughout it

http://forums.justcommodores.com.au...-demister-when-uphill-grade-vacuum-issue.html

Theres a vacuum solenoid under the radio area that controls the air flow to the windscreen. The internal rubber diaphram shreads itself causing a vacuum leak. Under heavy engine load (like going hard off a set of lights or up a hill) the pressure must build and it flicks the vent til the pressures released (back off throttle / top of hill).

Had it in my WK a year ago - changed that solenoid and havent had an issue since.