How to fix heater on 1989 f150 ford truck?

How to fix heater on 1989 f150 ford truck?

Depends what went wrong with it? If it is just blowing cold, it may be the thermostat which is dirt cheap and easy to fix. On the harder side, could be the heater core clogging up with gunk. If it was the heater core, your windows would always fog up and it would leak coolant. If it isn't doing those things, then change the coolant and pick up a 5 dollar thermostat and your good to go. If none of this works, go to the truckstop and buy one of those cigarette lighter heaters and throw it on the dash. Give you some heat and clear the windows better then freezing.