No heat.

[bpmassaro]

Blower motor runs , truck is at temp, no heat. Plus the air conditioning works but only for about 20 min. Seems like it doesn't really blow good either. 1996 tahoe . I replaced the heater control valve , no heat.

 

[tonymania]

Your heater core may be broken.

 

[MO Viet Vet]

The heater core may be clogged. Get a temp reading at both the in and out hoses when up to full temp. They should be fairly close in temp. You also may have a blend door problem but need to check basics first. Is the coolant low and do you have a coolant leak in the system? To get proper heat you need full coolant and good flow.

 

[LanaG]

Hi, I am experiencing this same issue. It is 9 degrees in Nebraska today and my heat did not work at all, I have replaced the blend actuator already, before if I turned the system on & off it would come back on, not today!! Think it is most likely the heater core? Can a mechanic tell if it is the heater core? Thanks!!!

 

[lesterl]

Heater core is probably plugged up. Pull the heater hoses off (engine cold) and tie them back and up. Use a garden hose to flush one port then move to the other, then back, keep it up until it flows freely. Re attach hoses, refill coolant, test run.