02 sierra clock resetting

[fishingstar]

The clock in my pickup resets just by turning the key to the on position.

It doesn't do it all the time more now that its cold out about 75% of the time only couple times a week during the fall.

anybody run into this before?

Dan

[Macgyver55]

Normally this is caused by low voltage. If the battery is questionable and/or there is a large draw it can cause the memory to reset when turning on the key.

[fishingstar]

the battery tested good. When it happens it does it before you turn the key to start. could it be in the ignition system? key switch?

Dan

[delcecchi]

(not a mechanic but I drive a car)

When you turn on the switch, the fuel pump, the fan, and a bunch of other stuff turns on. If there is a bad connection or something the voltage could drop far enough to cause a problem.

If you have an analog meter you could connect it to the lighter socket and turn on the key to see how much the voltage drops. I don't know if a digital meter is fast enough to see it.