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Temperature Door Motor/Var. Resistor
- Thread starter mandzo
- Start date
Temperature Door Motor/Var. Resistor
The actual problem I noticed a week ago is:The air flow of the heating system decrease gradually after 30 min usage to the point it completely disappear ( it doesn't matter where the flow is directed to - the windshield, side windows, the front or the floor). In the same time I could hear the blower is working ( it sounds normal). If I stop the engine for a couple of hours and start the car again, the flow is still NOT presented. If I wait 5-6 hours (35 degree outside temperature) and start the car, the air flow of the heating system is normal. I don't know much about the heating system and how exactly is working in regard to the TEMPERATURE DOOR (Temperature Door Motor/Var. Resistor). I was thinking for 2 possible reasons:1. Some how the fan of the blower disengage of the blower motor after 30 min work, but it's hard to explain why would work again after 5-6 hours.2 The temperature door start closing slowly because of malfunctioning of the Var.Resistor ( it looks this resistor controls the Temperature Door Motor) So having this in mind , I was thinking to replace the Var.Resistor like eventual fix - hopefully it is easy to reach.
The actual problem I noticed a week ago is:The air flow of the heating system decrease gradually after 30 min usage to the point it completely disappear ( it doesn't matter where the flow is directed to - the windshield, side windows, the front or the floor). In the same time I could hear the blower is working ( it sounds normal). If I stop the engine for a couple of hours and start the car again, the flow is still NOT presented. If I wait 5-6 hours (35 degree outside temperature) and start the car, the air flow of the heating system is normal. I don't know much about the heating system and how exactly is working in regard to the TEMPERATURE DOOR (Temperature Door Motor/Var. Resistor). I was thinking for 2 possible reasons:1. Some how the fan of the blower disengage of the blower motor after 30 min work, but it's hard to explain why would work again after 5-6 hours.2 The temperature door start closing slowly because of malfunctioning of the Var.Resistor ( it looks this resistor controls the Temperature Door Motor) So having this in mind , I was thinking to replace the Var.Resistor like eventual fix - hopefully it is easy to reach.
The first thing to do is to check if the fuse holder for the blower fuse (under dash and left of steering column) is loose or rusted. If it is loose, that might cause the blower to stop.
If that checks out fine, check if the blower fan motor is about to go.
It is most probably NOT the blower resistor. If the blower resistor goes bad, the fan will be on high no matter what speed you switch it to.
Fuse issue
http://www.contour.org/ubbthreads/s...er=1056473&page=&view=&sb=5&o=&fpart=all&vc=1
Blower motor in Autozonelink.
http://www.autozone.com/az/cds/en_us/0900823d/80/1b/cf/25/0900823d801bcf25/repairInfoPages.htm
If that checks out fine, check if the blower fan motor is about to go.
It is most probably NOT the blower resistor. If the blower resistor goes bad, the fan will be on high no matter what speed you switch it to.
Fuse issue
http://www.contour.org/ubbthreads/s...er=1056473&page=&view=&sb=5&o=&fpart=all&vc=1
Blower motor in Autozonelink.
http://www.autozone.com/az/cds/en_us/0900823d/80/1b/cf/25/0900823d801bcf25/repairInfoPages.htm
Last edited:
Temperature Door Motor/Var. Resistor
Thank you for the Info Tony!
Unfortunately it isn't the blow motor. It is working fine all the time. With a cold engine, the heating is working fine. In 30 mins, the air flow start to decrease gradually. I suspect the temperature door( or the FLAP door) is closing because the Var.Resistor is malfunctioning. So I need to find where this Resistor is located. Any Info will be mach appreciated, Thanks!
Thank you for the Info Tony!
Unfortunately it isn't the blow motor. It is working fine all the time. With a cold engine, the heating is working fine. In 30 mins, the air flow start to decrease gradually. I suspect the temperature door( or the FLAP door) is closing because the Var.Resistor is malfunctioning. So I need to find where this Resistor is located. Any Info will be mach appreciated, Thanks!
Not sure what variable resistor you are talking about but check out the autozonelink Vacuum Actuator Motor and the other link for Blend Door Actuator.Thank you for the Info Tony!
Unfortunately it isn't the blow motor. It is working fine all the time. With a cold engine, the heating is working fine. In 30 mins, the air flow start to decrease gradually. I suspect the temperature door( or the FLAP door) is closing because the Var.Resistor is malfunctioning. So I need to find where this Resistor is located. Any Info will be mach appreciated, Thanks!
http://www.autozone.com/az/cds/en_us/0900823d/80/1b/cf/77/0900823d801bcf77/repairInfoPages.htm
projectSHO89
Hard-core CEG'er
Thank you for the Info Tony!
Unfortunately it isn't the blow motor. It is working fine all the time. With a cold engine, the heating is working fine. In 30 mins, the air flow start to decrease gradually. I suspect the temperature door( or the FLAP door) is closing because the Var.Resistor is malfunctioning. So I need to find where this Resistor is located. Any Info will be mach appreciated, Thanks!
The "resistor" you're referring to is for the feedback to the blend door flap. It ain't your problem. If the blend door fails, you don't loose airflow, you loose temperature control.
Air direction is controlled exclusively by vacuum operated motors that move doors inside the plenum. Fail-safe airflow is to the defrost vents if control is lost.
If your volume of airflow is decreasing and is not simply being directed to another outlet, the most common reason is that the evaporator is freezing up (if you have been using a mode that runs the compressor). Simplest way to check is to disable the compressor and see if the symptom does not reappear. If so, the low pressure cycling switch is probably stuck in the closed position. Also, a frozen evaporator will be just fine after it defrosts, usually leaving an unusually large puddle under the car.
Steve
Temperature Door Motor/Var. Resistor
Steve, you are probably right.
I just checked, there are 2 puddles under the car. I also found the low pressure cycling switch on the top of the accumulator/dehydrator. Are you saying my A/C was ON all the time? I was looking on the electrical diagram for the A/C and heater blow and noticed that the low pressure cycling switch, the dual pressure switch and the heater mode switch(for A/C mode) are in a serial circuit, so in order for the A/C compressor clutch to be engaged, all have to be closed. I know for sure that the heater mode switch is in a "DEFROST/FLOOR" position. Anyway, I will try disconecting the electrical connector of the low pressure cycling switch, which should disable the compressor for sure. Does this sound right? Thanks
Steve, you are probably right.
I just checked, there are 2 puddles under the car. I also found the low pressure cycling switch on the top of the accumulator/dehydrator. Are you saying my A/C was ON all the time? I was looking on the electrical diagram for the A/C and heater blow and noticed that the low pressure cycling switch, the dual pressure switch and the heater mode switch(for A/C mode) are in a serial circuit, so in order for the A/C compressor clutch to be engaged, all have to be closed. I know for sure that the heater mode switch is in a "DEFROST/FLOOR" position. Anyway, I will try disconecting the electrical connector of the low pressure cycling switch, which should disable the compressor for sure. Does this sound right? Thanks
projectSHO89
Hard-core CEG'er
Yep, sounds right. Observe which HVAC modes do not use the compressor, you can run those to test if needed.
Personally, I'd just pull the clutch relay due to it's ease of access.
Steve
Personally, I'd just pull the clutch relay due to it's ease of access.
Steve
Temperature Door Motor/Var. Resistor
Thanks Steve!
I'll do the same. Is it possible the problem to be with the clutch itself, if it can't disengage. Frankly. I didn't use the A/C too much last couple of years, it may have some rust. I also noticed last week that fuel mileage drop a little bit, which point me to running A/C all the time.
Thanks Steve!
I'll do the same. Is it possible the problem to be with the clutch itself, if it can't disengage. Frankly. I didn't use the A/C too much last couple of years, it may have some rust. I also noticed last week that fuel mileage drop a little bit, which point me to running A/C all the time.
projectSHO89
Hard-core CEG'er
Thanks Steve!
I'll do the same. Is it possible the problem to be with the clutch itself, if it can't disengage. Frankly. I didn't use the A/C too much last couple of years, it may have some rust. I also noticed last week that fuel mileage drop a little bit, which point me to running A/C all the time.
It's possible but not very probable. Remove power from the circuit if in doubt and see if the clutch free-wheels or not.
Stve
Explain exactly the problem is. Is your heater only working on the defrost mode?
I've been having a similar problem with my heater only blowing through the defroster. I just replaced the A/C Temp Valve (Motorcraft PN F5RZ-19B888-B) and it did not resolve the problem. Any help is appreciated.
This is a vacuum issue.I've been having a similar problem with my heater only blowing through the defroster. I just replaced the A/C Temp Valve (Motorcraft PN F5RZ-19B888-B) and it did not resolve the problem. Any help is appreciated.
http://www.contour.org/FAQ/FAQ.php?s=probs&displayid=26
Its my understanding that on most cars (?) when you have it in defrost mode (windsheild or windsheild/floor) that the compressor runs? I have no idea why it does this but it does on most cars i ride in. Can hear it turning off and on. Maybe yours just keeps running the whole time you have HVAC on and freezes over?
Yes, to dry out the air so that the front windshield does not fog up. DEF or FLR/DEF on the Contour.Its my understanding that on most cars (?) when you have it in defrost mode (windsheild or windsheild/floor) that the compressor runs? ...
Temperature Door Motor/Var. Resistor
The problem was with the compressor. The clutch was engaged all the time and as Steve pointed me out the evaporator was freezing. This caused stop of the flow of hot air. Most of the time, I was driving in a FLR/DEF mode. Using AC clutch field kit( part# FMC F3SZ 19V649 CARM), the problem was fixed. Thank you guys for all advices!
P.P. And actually the tread should be renamed to "AC compressor clutch problem - no HEAT after 30min"
The problem was with the compressor. The clutch was engaged all the time and as Steve pointed me out the evaporator was freezing. This caused stop of the flow of hot air. Most of the time, I was driving in a FLR/DEF mode. Using AC clutch field kit( part# FMC F3SZ 19V649 CARM), the problem was fixed. Thank you guys for all advices!
P.P. And actually the tread should be renamed to "AC compressor clutch problem - no HEAT after 30min"
the reason for the ac pump to run when using defrost is one to dry the air and two so the pump doesnt sieze from lack of use ....................sorry Tony2005 didn't see that you beat me to itIts my understanding that on most cars (?) when you have it in defrost mode (windsheild or windsheild/floor) that the compressor runs? I have no idea why it does this but it does on most cars i ride in. Can hear it turning off and on. Maybe yours just keeps running the whole time you have HVAC on and freezes over?
I always forget about this. In the older cars (maybe early 80s), this was was very critical as the A/C was not designed to come on with the defrost mode. I was always advised to run the A/C on the older cars every few weeks or so during the winter.the reason for the ac pump to run when using defrost is one to dry the air and two so the pump doesnt sieze from lack of use ......................