sup guys, my 91 Ranger has none to very little "and its random when it does" heat in the cab...fan blows fine, heater core is fine, it seems like something is either stuck open in the ducts or not opening...hoping someone has delt with this before and can give me a idea were to start..I'm in WV and its been a rough winter and then to have no heat....NOT GOOD! Thanks!

 

Check your coolant level and your hoses. If there's an air bubble in the system or if your coolant's low, you won't get heat in your truck (won't allow coolant into the heatercore). Is your engine operating at normal temps? If not, some cardboard behind your grille will help the engine warm up better but I'm pretty you guys are only getting like 20* temps, not -40*. Your truck should run normally in 20*.

Only other thing I could think of off the top of my head is that the heater control isn't switching the duct back and forth to let the warm air into your cab. Is there proper resistance when you switch it back and forth (pretty sure '91s have cable actuated heat controls)? LR

 

As stated check the coolant level at the radiator. With the engine warmed up check the upper and lower radiator hoses. Are both hoses hot to touch? Check the heater core hoses where they pass through the firewall. Are both hoses hot to touch?