factory clocks that do not keep accurate time

[biscaynesix]

The factory clocks have a built in mechanism to correct for inaccurate time keeping. One of the posts said the clock lost an hour a day.....My 1977 Firebird Owners Manual clued me in to this one.....If you set the clock to the accurate time 3 days in a row at the same time each day, (say at 8AM each day) it should, after the third day keep the accurate time. When settiing the clock for day light savings/standard time, you must adjust the clock one and one half hours foward or back and then compensate for the half hour...i.e. when daylight savings begins, an accurate clock reading 4:00 would have to be set to 5:30, and then immediately backed up to 5:00 and it will keep the accurate time. If you just set it to 5:00 then it will begin to read fast.

[75-K5]

Weeeeird, but good info!