BEFORE DEPARTING PHOENIX, AZ, THE PLT OBTAINED A WX BRIEFING, WAS ADVISED OF FORCASTED ICING CONDITIONS & WAS INFORMED THAT THE SALT LAKE CITY (SLC) VORTAC WAS OUT OF SERVICE. WHILE EN ROUTE, AT 0931, HE RECEIVED A WX UPDATE. THE SLC WX AT THAT TIME WAS, IN PART: 2200 BROKEN, 5000 OVERCAST, VISIBILITY 20, LIGHT RAIN SHOWERS WITH PRECIP HEAVIER SE THRU SW,TOWERING CUMULUS SW THRU W. THE FORCAST WAS FOR 1000 FT CEILING, SKY OBCURED, VISIBILITY 1 MI WITH SNOW SHOWERS. HE WAS ADVISED THAT ELY, NV WAS CLEAR & COULD CONSIDER DEVIATING TO THE WEST, IF NECESSARY. AT 1036, THE PLT CALLED SLC TOWER. HIS TRANSMISSIONS WERE BROKEN, BUT ANOTER PLT RELAYED THAT HE WAS NEAR TOOELE, UT, BETWEEN LAYERS, VFR & WANT DISTANCE INFO. SHORTLY AFTER THAT RADIO CONTACT WAS LOST. WHEN THE ACFT DID NOT ARRIVE, A SEARCH WAS INITIATED. ON 3/29/83, IT WAS FOUND WHERE IT HAD IMPACTED THE SIDE OF FARNSWORTH PEAK BETWEEN TOOELE & SLC. ITAP INFO SHOWED THAT THE ACFT HAD TRACKED NORTHBOUND BEYOUND TOOELE TO THE GREAT SALT LAKE, THEN EAST TOWARD SLC. TOOELE WX: IMC, LOW CIG, SNO, MTN OBSCD.