B727 CARGO FLT ON TAXI OUT DISCOVERED WINDSHIELD OVERHEAT. DISCUSSED WITH DISPATCHER AND AGREED OK TO CONTINUE SINCE THOUGHT NO ICING CONDITIONS FORECAST FOR RTE. DISCOVERED ON ARR GEG ICING WAS FORECAST. DID NOT ENCOUNTER ANY ICING.

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THE CAPT'S WINDSHIELD OVERHEAT ILLUMINATED TAXIING OUT. RESET SWITCH AFTER 5 MINS COOLING WAS NO HELP. WE HAD OUR RAMP CALL OUR SPECIALIST (DISPATCHER) AND ASK HIM FOR HIS INITIALS AND TIME STAMP FOR A RE-RELEASE WITH OUR WINDOW (CAPT) INOP. THE MEL SAID WE COULD NOT GO INTO KNOWN OR FORECAST ICING CONDITIONS. THE WX THAT WE HAD FROM OUR PREFLT DID NOT SHOW ANY ICING FORECAST FOR OUR CALGARY TO SPOKANE FLT. HOWEVER; OUR NORMAL PRINTOUT OF WX ONLY HAS SEQUENCES; FORECASTS; NOTAMS AND SIGMETS. OUR DISPATCH SPECIALIST RELEASED US WITH A TIME AND INITIALS. I ASSUMED THAT HE CHKED ALL SOURCES AND DID NOT FIND ANY FORECAST OR KNOWN ICING CONDITIONS ON OUR RTE. OUR FLT WAS UNEVENTFUL; WITH NO ICING OBSERVED. ON ARR AT SPOKANE; IN CHKING THE WX FOR OUR NEXT LEG; I FOUND THAT THERE WAS AN AREA FORECAST FOR THE SPOKANE AREA THAT FORECAST LIGHT TO MODERATE ICING. THE DISPATCH SPECIALIST EITHER ASSUMED WE KNEW THE WX AND WANTED TO VIOLATE FARS; SO HE RELEASED US OR HE DIDN'T CHK THE WX. LESSON LEARNED: I SHOULD BE MORE SPECIFIC WITH MY REQUESTS AND NEVER ASSUME.