I was cruising down the interstate doing about 70mph, all of a sudden, my "Fasten seat belt" indicator light above started flashing. I counted the number of flashes to be '6' times at several instances. I didn't see anything unusual at the instruments, no MILs were lit. The engine didn't exhibit any abnormal behavior. There was no fault code stored at the X-plug by the battery. Anyone with same experience care to share their thoughts? I shall appreciate a valid investigating point.

1989 190E 2.6/ 175K miles
Last discrepancy was no start which I have replaced the Crank Position Sensor for a good fix. Several other parts were also replaced in that process such as: OVP relay, fuel pump relay, EZL module, coil, cap & rotor, wires & plugs and the aux. fan resistor.