Gilly, I came across this problem / description. Any additional insight you can give to the quote below? What does this fan do? The site the author links to for pics no longer works... so a more detailed description would be helpful. Is the diagnosis correct?
thanks!

==========quote=========
From Sam Truong (Sam_Truong@adc.com):

Ok, here are the step by step (from Tom DeTemple) with some minor modification and the pictures:

1. The front of the fuse box has a cover with two tabs. Press down heavily on the cover and flip the tabs off. Remover the cover exposing the fuse board.
2. From the front of the car, you will see two screws at the front. Unscrew the back pair until they are loose using the correct Torx or a 7/64" Allen wrench.
3. From the side of the fender, you will see three more screws on top of the black plastic cover with the emissions tags on it. Unscrew these until they are loose.
4. The cover should now easily come off.
5. From the side, look down towards the rear of the box and you will see a black cylinder (motor) with a Bosch sticker on it. That's the fan motor attached to the squirrel cage assembly below it.
6. Access to the fan you need to make room by pushing all cables to a side (see pictures)
7. Push back two clips. You need to wiggle the motor out of the inlet/outlet air hoses (see pictures)
8. I vacuumed dirt from the motor and inlet/outlet air hoses using my shop-vac. I also lubricated the bearings (per Wolfgang)
9. I tested the motor prior to reinstall by turning your ignition to the last position prior to start your trunk ( I don't know the correct terminology for this position).

Pictures
http://homepage.mac.com/koolimacsam/PhotoAlbum6.html

Result:
The noise went away and I didn't have to spend $80 to $100 to replace the motor. This task took me about 20 minutes.

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The fan keeps the module box at a optimal temp-not too hot or cold. It draws in air straight from the cabin, making use of the climate controlled interior of the truck. Kind of the same idea as the small cooling fan your PC has.
It can cause a squeeking noise with the truck running or up to 5 minutes after shut-down. It runs at the same time as the aux cooling pump, same circuit.
It may be adviseable to put a few old towels on the left fender before doing this, and also disconnecting the battery.
It's way at the bottom of the box. It comes out fairly easy but can be a bit of a puzzle to reinstall.
We've tried lubing/cleaning, but it always comes back (sounds OK when it leaves though!). We just replace them, but I realize they are fairly expensive for what you get.
The instructions seem to be pretty good otherwise.

Gilly

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My southern CA dealer wants $220 for a replacement fan. This is parts only, no labor!!!!

I followed your instructions and it seems to work, at least for now.

Thanks