HVAC controls bleeding down?
12-02-2016, 11:32 AM
#1
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Year: 1990
Model: Cherokee
Engine: 4.0
HVAC controls bleeding down?
1990 4.0l
When I shut the Jeep off with the heat running on floor (verified it is blowing on floor) it sounds like a hissing sound from the passenger foot well like a blow off valve. Not loud, just the diminishing air escaping sound. Clear as mud? Is this normal or should I look for a leaking vacuum component?
With the engine off I have pulled a vacuum on the line going into the vacuum ball and it held, no leaks.
When I shut the Jeep off with the heat running on floor (verified it is blowing on floor) it sounds like a hissing sound from the passenger foot well like a blow off valve. Not loud, just the diminishing air escaping sound. Clear as mud? Is this normal or should I look for a leaking vacuum component?
With the engine off I have pulled a vacuum on the line going into the vacuum ball and it held, no leaks.
12-02-2016, 05:58 PM
#3
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Location: Canton, MI
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Year: 1999
Model: Cherokee
Engine: 4.0
1990 4.0l
When I shut the Jeep off with the heat running on floor (verified it is blowing on floor) it sounds like a hissing sound from the passenger foot well like a blow off valve. Not loud, just the diminishing air escaping sound. Clear as mud? Is this normal or should I look for a leaking vacuum component?
With the engine off I have pulled a vacuum on the line going into the vacuum ball and it held, no leaks.
When I shut the Jeep off with the heat running on floor (verified it is blowing on floor) it sounds like a hissing sound from the passenger foot well like a blow off valve. Not loud, just the diminishing air escaping sound. Clear as mud? Is this normal or should I look for a leaking vacuum component?
With the engine off I have pulled a vacuum on the line going into the vacuum ball and it held, no leaks.
Have you tried it with the HVAC controls off before hutting down?
12-03-2016, 07:49 AM
#5
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Year: 1999
Model: Cherokee
Engine: 4.0
Turn the controls OFF before shut down as a regular operation.
Remove the cover off the blower resistor (see pic) so you can see the recirc air door actuator. See post #2.
With the engine running and the controls to heat, shut down the engine and see/hear if the recirc air door actuator is your problem.
Do the same with the controls OFF.
.
Remove the cover off the blower resistor (see pic) so you can see the recirc air door actuator. See post #2.
With the engine running and the controls to heat, shut down the engine and see/hear if the recirc air door actuator is your problem.
Do the same with the controls OFF.
.
Last edited by CCKen; 12-03-2016 at 09:09 AM.