wareaglewild85
New member
The blower works fine, but the heater has quit putting out warm air. Is this a fuse issue or something more costly? Thanks!
Heater Quit
- Thread starter wareaglewild85
- Start date
SteelHeadz
Super Moderator
With the engine temperature on cold. Disconnect both heater core lines from the engine compartment. Install a waterhose on one end then slowly open the faucet till the flow through the other end of the heater core is as much pressure as your pumping into it. If you have a lot of restrictions within the core, the flow will be poor and this may indicate a more thourough flush or replacement in the worse case scenario. A good indication of a clogged heater core is when you apply throttle, the heat output will increase and decrease at idle.
JPNinPA
Well-known member
There is some poor jeep info here. I'll discuss later.
What year TJ?
You have airflow but no heat and no overheating issues? Continue.
First, These are the things to review:
1.) Is your radiator and overflow filled? If not fill it and go to the next.
2.) Is there air in the system? If your not sure, with the engine cold open the radiator and start the engine. Let it heat and watch for bubbles to come out. Once at temp you should see the fluid moving. Squeeze the top rad hose to help the air through. Top Off the rad and close it up.
3.) While warming up feel the upper and lower heater hoses. They should be hot about the same temp. If not follow what SteelHeadz mentioned above. Flush the heater core. Might think about doing the entire system but the heater is what is an issue. Burp the system as above.
4.) If the hoses are hot and all else checked out check the blend door. It blends outside air with recirculated air. Based on the model it may be mechanical where the cable falls off or the door breaks. Or electrical where the motor fails or connections are bad.
5.) Inspect the temp select switch on the dash. Tubing/wiring may be bad.
6.) If you haven't fixed it by now inspect the heater core for debris that may be blocking the air from flowing.
What year TJ?
You have airflow but no heat and no overheating issues? Continue.
First, These are the things to review:
1.) Is your radiator and overflow filled? If not fill it and go to the next.
2.) Is there air in the system? If your not sure, with the engine cold open the radiator and start the engine. Let it heat and watch for bubbles to come out. Once at temp you should see the fluid moving. Squeeze the top rad hose to help the air through. Top Off the rad and close it up.
3.) While warming up feel the upper and lower heater hoses. They should be hot about the same temp. If not follow what SteelHeadz mentioned above. Flush the heater core. Might think about doing the entire system but the heater is what is an issue. Burp the system as above.
4.) If the hoses are hot and all else checked out check the blend door. It blends outside air with recirculated air. Based on the model it may be mechanical where the cable falls off or the door breaks. Or electrical where the motor fails or connections are bad.
5.) Inspect the temp select switch on the dash. Tubing/wiring may be bad.
6.) If you haven't fixed it by now inspect the heater core for debris that may be blocking the air from flowing.
Last edited:
JPNinPA
Well-known member
Now for the bad news. TJ' heating/cooling system recirculates the coolant through the engine and heater core all the time while the engine is running. There is no valve to shut off or bypass he hater core. So even if the thermostat is stuck closed you should have heat.
Also even with no thermostat ( and I do not advise running with out one) there is enough restriction in the radiator to force fluid to the heater core.
just correcting not bashing anyone.
Also even with no thermostat ( and I do not advise running with out one) there is enough restriction in the radiator to force fluid to the heater core.
just correcting not bashing anyone.
JohnnyO
New member
No offense taken. I have had the heater control valve go bad on two other vehicles I've owned and figured it could be the same problem here.
Similar threads
