Never saw myself as much of a mechanic, but here I am replacing a vacuum actuator that helps direct the airflow in a motor vehicle. This is chapter two of a five-part series on the Holden VY Series II. I tried a few things to get it working as best as possible. Some things I succeeded at, others I didn’t. Join me on this weird journey of retro car repair!

We found that the airflow kept diverting to the windscreen when other modes were selected, particularly under engine load above roughly 2000 RPM. The mode actuators run on inlet-manifold vacuum, with a tank and check valve keeping a reserve when that vacuum drops. I was hoping that replacing one actuator would rule out a possible leak. We picked up a “Commodore Vacuum Actuator Air Vent Control VT VX VY VZ Genuine Holden NEW” for $77 shipped. The hoses, check valve, vacuum tank, other actuators and solenoid pack were still possible places to investigate. Plenty left to chase!

First I needed to actually find the thing. I started on the passenger side, pulling down the glove box and removing a few trim panels. Fortunately, I’d already replaced the glove box clips some time ago, so at least that part was behaving itself. The actuator, however, was rather more difficult to reach than I’d hoped.

After a bit more investigating I ended up over on the driver’s side, removing the lower trim to get access to the mechanism. There are several coloured vacuum hoses running around the area, and I’d found a diagram showing where they should go. Handy, because I certainly wasn’t going to remember them all!

The actuator I could reach had pink and orange hoses, which helped identify it against the diagram. The other actuator was tucked away in a considerably less friendly position. Since I’d already got this far, I decided to replace the accessible one and see whether that helped the problem.

Naturally, one of the screws managed to escape while I was removing the old actuator. It disappeared onto the driveway, which was almost exactly the same colour as the screw. Wonderful! At least I’d managed to get the replacement into position, even if the tools and fasteners weren’t being particularly cooperative.

With everything reassembled, I started testing the different ventilation settings. The little flaps were certainly moving, and there was a rather interesting popping noise whenever the new actuator changed position. I spent a while switching between windscreen, floor and face ventilation to see how it behaved.

It seemed somewhat better with the engine running, so I took the car for a drive. Unfortunately, the airflow could still return to the windscreen under some conditions. At least the replacement had made a difference, even if it hadn’t completely sorted out the problem.

I suspect the other actuator may still need attention, but getting to that one looks like a considerably larger adventure. For the time being the system is behaving better than it was, and I think I’ll leave the more difficult repair for another day!

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