Runnining with no hot air in the Jeep for a while now. Finally got around to digging into it. Found out the radiator was leaking so while i was in there went ahead and replaced it along with the thermostat. Also went ahead and flushed out the heater core. Before the outlet hose would not get that hot. Now it gets unbearably hot like the inlet hose. When running the engine to temp i have noticed that stays steadily below 210. Before the replacement there would be no hot air at all. Now its luke warm at best. I ran several flushes until the water came out crystal clear. I checked the blend door actuator, and it seems to be working as well. There are no leaks that i can tell so not sure where to go next. Could the water pump be out? Or am i actually looking at a bad heater core?
Luke warm Air
- Thread starter Hashmeir
- Start date
Probably a bad new thermostat.
I went through several before I bought a Robert Shaw sourced from Flowkooler.
-Mac
I went through several before I bought a Robert Shaw sourced from Flowkooler.
-Mac
Rancho LJ
Member
How did you test the blend door actuator? Did you try manually moving the blend door with the actuator removed?
I did not try it manually. Only turned the dial and confirmed the actuator moved when turned to heat.
KennethS
TJ Addict
Rancho LJ
Member
Assuming the 03 is similar to the 05, you can access the actuator from the passenger side footwell. Let the engine heat up so you have hot fluid flowing through heater core. Both hoses in and out of heater core should be hot. You can use an infrared thermometer to check temps. Remove the three screws (8mm I believe) and let the actuator drop. Turn the shaft manually on the blend door in both directions to the stops. You should feel a difference in temp when moving from on direction to the other. If the shaft spins free without change in temp, the blend door is bad. With the actuator removed, move the temp control from hot to cold to make sure the actuator moves both ways and stops.
The first photo below shows the bottom view of actuator. The second shows the blend door inside the HVAC case.
Although I haven't tried it myself, there is procedure for resetting the actuator position:
To reset the blend door actuator on a Jeep Wrangler TJ, disconnect the negative battery cable for a few minutes, reconnect it, start the Jeep, and then cycle through all your HVAC vent modes (defrost, floor, dash, mix) while the engine idles, allowing the actuator to recalibrate by listening for it to move and click into place. If that fails, you might need to manually align the actuator arm with the blend door or replace a broken actuator, as resets work best after a replacement or minor glitch, not a full mechanical failure.
Hopefully this helps your troubleshoot the problem.
The first photo below shows the bottom view of actuator. The second shows the blend door inside the HVAC case.
Although I haven't tried it myself, there is procedure for resetting the actuator position:
To reset the blend door actuator on a Jeep Wrangler TJ, disconnect the negative battery cable for a few minutes, reconnect it, start the Jeep, and then cycle through all your HVAC vent modes (defrost, floor, dash, mix) while the engine idles, allowing the actuator to recalibrate by listening for it to move and click into place. If that fails, you might need to manually align the actuator arm with the blend door or replace a broken actuator, as resets work best after a replacement or minor glitch, not a full mechanical failure.
Hopefully this helps your troubleshoot the problem.
Last edited:
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