12 section 180 1973 79 TRUCK SERIES 100 500 YEAR MODEL RESTRICTIONS PART NUMBER DESCRIPTION TY 18549 CONTROL ASSY HEATER 73 74 E100 300 D3UZ 18549 A Not re laced 1 75 76 E100 350 w heater aux DSUZ 18549 A Includes main aux switch 1 heater W 73 F100 250 w aux fuel tank D3TZ 18531 A Not i gq 1 74 F100 aso w aux fuel tank D4TZ 18531 C Ingugg ta nk gvvit hjig gaced 1 73 74 F100 350 w 0 aux heater D3TZ 18531 B V A M M v 1 75 79 F100 350 w o aux fuel tank D9TZ 18549 E 1 w o deluxe heater vent 78 F100 250 w 0 aux fuel DBTZ 18549 B 1 tank w deluxe heater vent Not replaced Before Ser CAO 0O1 78 79 F100 350 w o aux fuel tank D9TZ 18549 F Control 1 with deluxe heater vent 78 F100 350 with aux fuel tank DBTZ 18549 M Control 1 w 0 deluxe heater vent From Ser CAO OO1 79 F100 350 with aux tank D9TZ 18549 C 1 w 0 deluxe heater vent 78 F100 350 w aux fuel DBTZ 18549 A 1 tank w deluxe heater vent Not replaced Before Ser CAO OO1 78 F100 350 with aux fuel tank D8TZ 18549 L Control 1 with deluxe heater vent Not replaced 8 82 From Ser CAO O01 vo F100 350 with aux tank oorz 18549 0 1 w deluxe heater vent Not re laced 77 79 E100 350 with aux heater D9UZ 18549 A Control 1 w 0 deluxe heater vent Not re laced 78 E100 350 with aux heater D9UZ 18549 D Control 1 with deluxe heater vent