slaskowski

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:

• 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 clues on what is happening (or perhaps about to happen - something about to go bad, etc)

Any help/clues would be appreciated.

Best - Steve

mike cap

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.

olsonreels

https://rennlist.com/forums/993-foru...diagnosis.html

This thread may offer some help.

ToreB

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

P-daddy

Yup, I just replaced both AC and oil cooler resistors on a friend’s 993 last weekend.

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badabing

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?

pp000830

[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.

ToreB

"a fan in the front of the car was cycling on/off, only with A/C on" = condenser fan. Period.
T

notabot

Whoa! Was that old guy still in one piece? Most of them are in pieces when you go to change them out.

P-daddy

Yes, I was surprised to find the originals still intact.

rgupta250

p-daddy, did you need to actually remove the front fenders or can the resistors be replaced from inside the left and right wheel wells?

​​​​​​​RG

slaskowski

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"

Assuming that I can just buy them from either Pelican or Sunset Porsche

slaskowski

Pdaddy - As per the question above - did you have to take off the fender or can you do it from inside the wheel well?

ToreB

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

mike cap

Take off the bumper cover to maintain your sanity. You can clean out the two radiators and replace the long disappeared sealing foam while you're at it.

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.