My wife has a 97 ford explorer V8 awd that had the heat stop working. It worked on the way into town, but when she drove it home it was cold air. Any ideas as to what I should try and how I can trouble shoot it?

 

Check to see if the blend door is broken. http://www.blenddoorfix.netfirms.com/
Also seach on this site for heater problems.

 

Was the temp gauge operating normally (mid range)? If it was reading low, it could be a stuck thermostat.

 

if the temp gauge read normal check both heater hoses where they go into the firewall if both hot poss blend door problem if one hot one cold poss has air lock, dirty heater core and water not passing through two type blend door problem on these unit one the electroinc accuator brakes ( gear inside strips) two the blend where the actuator mounts brakes apart good luck

 

Just for the heck of it check your coolant level. Might be low, & cold enough out side for you not to overheat. JUST MY .02

 

Another thing to check, if the heater hoses are not hot and the engine is up to temp, check the vacuum operated bypass valve.