Have you ever driven up to a gas pump, turned off your ignition and then had been unable to lower the window to tell the attendant what you want because the power-operated windows won't work?

Well, they don't work because of a 1970 regulation of the National Highway Traffic Safety Administration, and General Motors is trying to get it changed, according to the Aug. 4 Federal Register (pge 51628). It promises to be a clash between convenience and safety, with the question turning on whether a sophisticated new GM switching device is acceptable to the federal regulators.

In the late 1960s, before the NHTSA got into the picture, power windows could go up and down whether or not the car ignition was turned on. The windows became the object of play for children, and there were, according to an agency official, "several fatalities recorded."

As a result, NHTSA hearings led to a "rulemaking procedure that required car makers, as of Feb. 1, 1971, to make the windows inoperable if the ignition was not turned on.

GM, along with other manufacturers, has been receiving complaints ever since. Now the big auto manufacturer has come up with a new idea.

The power windows would work with the ignition key in the off position, but only if the doors on the car remain closed after the engine is turned off.

So, in the situtaion where a motorist pulled into a gas station, stopped by a pump and turned off the engine, the power windows would work as long as the driver remained behind the wheel and no one got out of the car.

The moment someone opened a door, however, the power windows no longer would work. If the driver left the car, for example, any children remaining in the car would not be able to play with the power windows. The windows would not work again until the ignition was turned on.

The NHTSA has agreed to look into the GM proposal and "explore the safety consequences" of the new switching device. Any decision is "about a year away," according to an agency official.