As I posted several months ago, I had a vibration in my HVAC (heater / AC) fan in the dash on my 98 PA Ultra. I will post my findings for posterity, in case it may help someone else with their 1998-2005 PA fan removal for any other reason.
First I removed the air ducts under the glove box, on the passenger side of the dash. I may have removed the glove box to make seeing the fan easier.
The fan assembly is mounted to the heater housing with 3 combination screw / washers. I believe they were 10mm, but don't remember for sure. The fan assembly is mounted with the fan up and the motor down. Besides the screws, an electrical connector for the motor which must be disconnected. There is a safety catch on the connector that needs pried up with a small screwdriver, while pulling the connectors apart.
Additionally there is a rubber cooling hose that supplies air flow to cool the fan motor. The hose is shown disconnected in the picture. You can see that the cooling hose has a groove that snaps into the hole in the side of the fan motor. One of the screw / washers is a very close clearance to the motor cooling hose. It's the one almost under the hose in the picture. I was worried that the washer might rub the hose enough to put a hole in the hose. It was also hard to finger start the screw back in the hole due to the washer being pushed by the hose.
I ground some of that washer away so I could turn the washer to clear the hose better upon installation. It is a little awkward to catch the fan when you remove it, and even more so to hold it in place with one hand and start the screws with the other to replace it.
You can see the leaves and tree trash that was causing the fan to vibrate. I was tempted to fix a screen over the open end of the squirrel cage fan, but decided it might come loose later on and jam the fan. I suppose the cabin air filter is full of tree trash, but I replaced it once and it's not something I look forward to doing again. I am still getting good air flow to the ducts.
It turns out that the tree trash was caused by two problems. First the screen under the cowl air intake grille was missing on the driver's side (which was unfortunately the tree side). And also, the maple seeds that hit the windshield would slide down and then between the plastic air intake grille and the windshield getting into the air plenum for the heater fan. I will show the fix for that in another post.