Interior blower fan dissapears when accelerating

[rowdybloke]

Hi all

Does anyone know why my interior fan disappears from the front vents and gets redirected to my demister when I hard accelerate up hills then goes back to the front vents when I back off???

[Cheap6]

Yep.

It's a common problem.

There is a vacuum leak somewhere between the inlet manifold hose and the vent control system.

A search on here will bring up a few more threads on it but look for the leak in:

The one way valve in the hose from the manifold.

The spherical vacuum tank under the LH front guard, behind the bumper bar.

The heater tap.

The valve to the heater tap, behind the vent control dial.

The hose attachment to the manifold.

The vent control flap actuators.

The vent control dial.

[jetspin_vn]

This should be your first port of call. Refer attached image.

The pic shows the vaccum distribution lines from the inlet manifold. The vac pressure is used to move the selectors. The T Piece shown should be against the firewall right behind your throttle body.

The line marked 'B' runs from the T junction between the inlet vac line and the cabin selectors, down the the pressure accumulator under the left guard. As this line is open to the road under the car, it can easily become damaged over time and/or brittle leading to cracks.

A simple diagnostic... remove the line marked 'A' from the T piece, and connect it to the non return joiner marked 'D'. Take the car for a drive, if this solves the problem then take a good look at the line to the accumulator bulb.

Not guarenteed, but its the easiest fix of all. The rest are a pain in the arse. You can see from the pic that even my T piece to cabin line is getting old and discoloured.

Hope that helps.


EDIT: Just noticed your ride is a VS. Should still be a similar setup, just note the pic is from my VN.

[rowdybloke]

Thx 4 that. Will look at those options