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Door locks not locking and unlocking

We have a 2000 Expedition, 140,000 miles. The doors don’t lock or unlock at times. It happens on all 4 doors and the back hatch, usually one or two at a time. It’s getting worse; almost every time I lock or unlock it, at least one doesn’t work. Someone suggested a bad actuator, but would they all go out at almost the same time?

Is this from your remote or the master switch? I bet remote,could be a low battery in remote,failing remote,failing reciever,is the problem present with all remotes?

This happens with the remote key fob, the keyless button pad on the outside driver’s door, AND the inside lock/unlock buttons.

My experience is more with GM power locks,does the drivers lock/unlock all the time? GM"s require two fob presses of the key for othe doors,but yours fails off the master switch also,for me a look at the schematic and some signal testing is required at this point,mainly what module(s) relays are involved,but the problem could also be wiring related.2hrs diagnostic time and you should have a answer(GM always told us 30min is enough)

The driver door usually unlocks, but not always. The whole thing’s getting bad enough I guess I’d better get it in. Thanks.