BMW E53 X5 HVAC controller air sampling fan dash squeak rattle fix

[X5Boise]

Problem: Everytime I would open my door, I would hear a squeak or rattle like noise from the dash. I localized it to the HVAC controller. Even during drives, I would get a rattle like noise when stopping the car. It got pretty annoying.

Cause: BMW has an air temperature sampling fan in the HVAC controller that spins to accurately sample the air temperature. The fan is located behind the driver’s side vent hole on the HVAC controller. Over time, the fan gums up, gets dusty, and loses lubrication. The apparent squeaking and rattle like noise is attributed to this.

Fix: Take apart the HVAC controller unit, clean out the fan and lubricate it. Merely spraying a can of air into the unit is only a temporary fix—this is the best, most long-lasting fix.

Difficulty level: 2/10 easy

MATERIALS NEEDED

• Trim removal kit (for a surprisingly good quality, indispensible, inexpensive kit, get it from Freight Harbor Tools (4 Piece Nylon Pry Bar Installer Kit) About $6. Even cheaper than eBay.
  • http://www.harborfreight.com/4-piece-nylon-pry-bar-installer-kit-95214.html
  • Pretty much a MUST-HAVE for this job and for working on any car’s miscellaneous interior/exterior trim
• Shop towel (to protect the wood trim)
• Isopropyl alcohol (to clean the fan)
• White lithium grease (for fan lubrication)

PROCEDURE

1. Preparation. Put the car ignition in ON (but don’t start the car). Shift to “N”. Pull the parking brake. Put a towel on the wood trim panel in front of the shifter (so you don’t scratch the wood trim panel). Turn the ignition to ACC to save on power.

2. HVAC Controller dash removal. With the 2 flat blades in the trim removal kit, insert them about 0.5 inches into the very outer side edges of the HVAC controller and tease out the HVAC controller unit. I did one side then the other. You will not damage the dash material—it’s pretty tough. See this video for help:

http://www.youtube.com/watch?v=GAh6dvpZFkA



3. Unplug HVAC connectors. There are 4 connectors on the underside of the HVAC controller. The two middle connectors are held in by swing arm type connectors—push down the tab and the swing arm rotates 90 degrees and the connectors pop out. The large black power cord is held in by clips on the side—squeeze both tab ends, and wiggle out the connector out. The small 3 wire connector gave me trouble in removing the connector, but through some coaxing, I was able to get it disconnected as well.

4. Remove HVAC controller trim panel. There are some tabs on the top and bottom of the outer HVAC trim piece that you need to just lift up and it will allow you to slide the trim panel back to remove it.

5. HVAC controller back cover removal. The back panel cup of the HVAC controller has about 8 plastic tabs that hold it to the face of the HVAC controller. You can separate the tabs with your hands/fingernails by lifting up the lip—do this for all eight and the back panel cup comes right off to expose the electronics and fan.

6. Fan removal. Just pull the fan straight up and out—it’s only held there magnetically. I cleaned the fan with isopropyl alcohol (wait about 2 minutes to dry), then before putting it back in, I lubricated the metal spinning axis spindle with some white lithium grease (durable lubricant that will adhere, is heat resistant, and is difficult to gum up). Don’t put too much on the stem—just enough plus a little “extra” (see picture). While apart I would clean out any dust in the fan sampling port.

7. Reassembly. To test the fan before reassembly, plug in the large power connector and the blue swing arm connector to the board (no need to connect the smallest power connector or the black swing arm connector yet). If the fan doesn’t squeak, you can disconnect all power cords and begin reassembly in reverse. If it still squeaks, add a little more white lithium grease to the metal spinning axis spindle.

Once you’re all done. Go ahead and open your doors and you’ll be greeted by a silent car, free of crickets, rattles, and squeaks from the HVAC controller.

[SlickGT1]

Holy shit nice. 2nd post no less. Like your style. Deffinatelly a good writeup. I too get a rattle that I can't pinpoint. Curious if it's the same thing. I thought mine was around glovebox area, but I can't reproduce it.

[X5Boise]

Originally, I found that the rattle dash noise would be replicated if I slowed down, this was probably caused by the plastic fan shifting on its axis. I'd also get a constant squeak from the HVAC controls. Once I permanently fixed the fan with durable white lithium grease, the rattle dash noise disappeared, along with the HVAC fan noise. Now I have what appears to be different intermittent rattle from the steering column and/or instrument cluster--next on thing to deal with...

[X5Ghost]

I have the same noise and was thinking it maybe a lot of work chasing noises! This is great, now I'll go after this one! Thx

[nezarnuaimat]

Good thread, thanks pal

[X5Boise]

UPDATE: I had the rattle like noise come back after about 3 weeks. It would come and go. When I took apart the magnetic motor during the original repair, it appeared to have some defects in the magnetic surface (a gouge and a few scrapes on the outer edges of the circular magnet). I didn't think much of it then--I thought it just needed lube. Obviously the imbalance in the magnet is causing it to develop hotspots on the spindle causing the squeak and rattle to return (see pics). How the gougles developed on my original magnet is a mystery (could be poor quality control when the magnet was originally assembled).

REMEDY: I bought a used 2003 BMW 3 series HVAC controller module from eBay ($40 shipped; bought from a 3 series as they are in ubiquitous supply and should result in lower cost), and took out the motor from that controller (cleaned it first, and inspected it to make sure it had a true, non-gouged surface) and directly transplanted it to my original X5 HVAC controller. You obviously could purchase a new motor from Papst (the fan manufacturer), but I didn't know the cost or if it even available as a direct purchase from the manufacturer (nonetheless, I would imagine that if someone contacted them, they might just sell it direct to you).

No issues since the replacement motor was put in as it's newly lubricated and it has a perfect magnet surface (so it can spin without a wobble). I can finally say the HVAC controller is now quiet as a whisper and should be permanently fixed.