Jump to content

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)

Anybody knows where are the relays for the radiator fans?

Recommended Posts

  • Admin

I've done many upon many cooling fan resistors and complete fan assemblies on 996's so I imagine the 997 is similar. The resistors clip near the bottom of the fans in front of the wheel wells.


No resistors on 997-1. The fans are controlled by electronics with their own control box.

From the Tech Book for the 997-1...

"An infinite fan control for the radiators has been introduced with the 3.6 litre and 3.8 litre engines of the new 911 Carrera and 911 Carrera S. This new feature permits infinite control of the fan speed as a function of the coolant temperature and the system pressure in the air conditioning system instead of two-stage control. It has the advantage of requiring less current and therefore creates less of a load on the

vehicle electrical system.

With staged control, when a temperature threshold was exceeded the next fan speed had to cover all of the allocated temperature range. With infinite control, the fan speed can be continuously adjusted to the actual requirement. This means that the fan speeds can often be reduced, thereby decreasing noise and vibrations."

  • Upvote 1
Link to comment
Share on other sites

Mine is a right hand drive car, so it is the driver's side for me!

It is close up to the side of the luggage compartment, right behind the fan unit, and from the diagram in the workshop manual it would be easy to mistake it for being inside. Just take off the wheel arch liner and you can't miss it, as you can easily see where the fans connect.

I wasn't sure if it was the fan or control unit, so (as someone has already suggested) I put a 12v supply direct to the fan, and it ran, so I knew it must be the control unit.

Link to comment
Share on other sites

  • Admin

You could test the fan motor directly by applying 12 volts positive at the fan wire connector junction point (remove wheel well liner to access).

Or unplug the fan and stick a volt meter in the socket.

I am not sure that will work - I think these are stepper motors now and they get a square wave as I recall.

Link to comment
Share on other sites

  • 2 months later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.