Reader offers a good tip unless you own a Saturn

Dear Car Talk:

You had a reader write in recently about a 2002 Saturn with air only coming from the defroster vents.

I had a 2000 Chevy Astro with the same problem. It started right after the dealer serviced it. The dealer told me it could cost $1,000 or more to take the dash apart. A year later, I took the car to an independent repair shop for regular service and asked about the air problem. The mechanic said it was probably a disconnected vacuum line. It was. He didn’t charge me to fix it.

Could that be the Saturn’s problem, too? —Dean

I don’t think so. Fortunately, it’s been a long time since I’ve worked on a 2002 Saturn ventilation system, so the memories - and the trauma - have faded.

But I don’t think that particular car used vacuum motors for its blend doors. While some cars use vacuum motors to control their duct flaps, I believe the 2002 Saturn used a servo, stepping motor.

So, a disconnected vacuum line shouldn’t have affected the vent system on that car. It could have caused other problems, though, like making the car idle poorly. And if someone reported to me that their ventilation doors were behaving strangely, and their car was idling poorly, I would put “vacuum leak” on the list of things to check for.

You were fortunate, Dean. The guy with the Saturn - Tom - probably got the same $1,000 “take the dashboard apart” estimate, and in his case, some poor mechanic had to spend a full day, upside down, with his head in the footwell and 20year-old crud falling into his eyes.

But it was good thinking, Dean. You’re not wrong in your logic. You just haven’t owned a 2002 Saturn. I’m sure Tom would be happy to remedy that for you if you’re interested.