Help

Justin beck · Sep 6, 2017

Ok this is my first post but I have a 96 f250 heavy duty 7.5l I had tremendous heat then one day it just stopped so I replaced the heater core thermostat and there was a vacuum line on the outside to operate that door still nothing then I replaced the whole control panel for the heat switches still nothing it blows cold air out everywhere but still has ac i don't know what to do any one wanna suggest something and there is no vacuume lines I can hear leaking

miesk5 · Sep 7, 2017

Yo Justin,
Welcome!
1996 Bronco/F-Series Workshop Manual, partial @ http://www.diesel-dave.com/vehic/manual/stj/ststjleft.htm

Go to

Section 12-00: Climate Control System, Service

DIAGNOSIS AND TESTING

Symptom Chart — Climate Control System

CLIMATE CONTROL SYSTEM

Condition

Possible Source

Action

Insufficient, Erratic, or No Heat

Low radiator coolant due to coolant leaks.

CHECK radiator cap pressure. REPLACE if below minimum pressure. FILL to specified coolant level. PRESSURE TEST for engine cooling system and heating system leaks. SERVICE as required.

Engine overheating.

REMOVE bugs, leaves, etc. from radiator and support or A/C condenser core fins. CHECK for:
Operation of engine fan clutchLoose drive beltSticking thermostatIncorrect ignition timingWater pump impeller damageRestricted cooling system
SERVICE as required.

Loose drive belt.

REPLACE drive belt if cracked or worn and ADJUST drive belt tension.

Thermostat.

FEEL heater water hoses. If the heater water hoses are too hot to hold, the thermostat is OK. If the heater water hoses do not get too hot to hold, REPLACE the thermostat. If only one heater water hose gets hot while the other remains cool, a plugged heater water hose or heater core is indicated.