front fan cycling on/off with AC turn on
#1
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I have a 1998 993 Cabriolet with about 23K miles based out of Miami Beach. I noticed the other day when rinsing her off after a spirited ride that a fan in the front of the car was cycling on/off. Details are as follows:
Any help/clues would be appreciated.
Best - Steve
- The fan would for run for 10 seconds then turn off for 20 seconds then turn back on for 10 seconds turn off for 20 etc.
- Only happens when the AC is turned on
- when the AC is turned off it would never turn on
- Would happen with the AC on both low/high and no matter the fan speed controlled by the AC unit
- The AC blows cold and the fan runs consistently inside the car.
- I have not run any Durametric codes yet but will do so what I get back into town
Any help/clues would be appreciated.
Best - Steve
#2
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Definitely not right. Should run all the time whenever AC is turned on either on high or low speed.
Probably a falling apart ballast resistor. Has it ever been changed that you know of?
Many here more knowledge about the AC then me that will point you in the right direction.
Probably a falling apart ballast resistor. Has it ever been changed that you know of?
Many here more knowledge about the AC then me that will point you in the right direction.
#4
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The A/C condenser fan low speed resistor is shot. This is a common fault, and the resistor needs to be changed. The condenser fan shall run on low speed when you turn on A/C, and if the low fan speed resistor is shot, the high pressure swich turns on full speed in intervals to keep the pressure and heat down. I would recommend to change the resistor asap, and also check the oil cooler low speed resistor at the same time. It is probably due for a chage too, while you have the front fender off. The job is done in an hour or so.
Cheers,
Tore
Cheers,
Tore
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AX993 (10-10-2020)
#6
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We may be jumping the gun here a bit.
OP, there are fans in the front of the car on both the driver side and passenger side corners.
Which fan is it that you hear?
OP, there are fans in the front of the car on both the driver side and passenger side corners.
Which fan is it that you hear?
Last edited by badabing; 10-10-2020 at 11:17 AM.
#7
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[QUOTE=slaskowski;16955258]I have a 1998 993 Cabriolet
Could it be normal the fan cycling on and off with the compressor? No need for the fan if the compressor is not running.
Could it be normal the fan cycling on and off with the compressor? No need for the fan if the compressor is not running.
Last edited by pp000830; 10-10-2020 at 11:52 AM.
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#8
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"a fan in the front of the car was cycling on/off, only with A/C on" = condenser fan. Period.
T
T
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#12
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Thanks for all the advice!! Looks like I know what I will be doing next weekend.
How long did it take to replace both resisters as I got a little nervous when you used the term "weekend"![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
Assuming that I can just buy them from either Pelican or Sunset Porsche
How long did it take to replace both resisters as I got a little nervous when you used the term "weekend"
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
Assuming that I can just buy them from either Pelican or Sunset Porsche
#14
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It is possible but a bit fiddly to change the condenser fan resistor without removing the front fender. If you want to do the oil cooler fan resistor the fender must off.
It is not difficult to remove the fender, I did this and change both resistors in about an hour.
Cheers,
Tore
It is not difficult to remove the fender, I did this and change both resistors in about an hour.
Cheers,
Tore
Last edited by ToreB; 10-11-2020 at 05:23 PM.
#15
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You can order the resistors, sealing foam pieces, headlight vent pieces and hardware ahead of time to limit your downtime. If you pm me I can send you the must have list.
Last edited by mike cap; 10-11-2020 at 05:44 PM.