Found something on Mud that mentioned a poor connection inside the clock between four small springs (located behind the connector, in the clock itself). The four springs connect the clock to the connector in some way. The springs can be stretched and contacts cleaned. I will tear into mine, too, and see if this fixes it.
Steve H. - KE0KNH
Colo Springs, CO
'78 FJ40, '89 FJ62, '98 4Runner