Last weekend when heading home from Summit County, CO (275 miles), my temp gauge light began to flash after filling the vehicle up for the drive.  Pulled into the adjacent parking lot and checked the coolant levels.  All were OK.  Upon restart, the light did the usual 3 second flash to indicate it was working, turned off and never came on again during the 6 hour drive (over 2 10,000 foot passes etc.)  

2 days later my wife pulls out of the driveway, the light goes on, she pulls over, checks fluid, restarts vehicle and light stays off.  Same scenario the next day on a 45 min drive.  The only anomaly, on the 45 min drive is after sitting for an hour, the temp seemed to climb to normal operating temp faster than usual.

Any clues where to start diagnosing this one?

Thanks,

Chris

Telluride, CO
'87 Westy