The blower on my 1994 530it has been intermittently making a gruesome squealing noise, so I figured it was time to replace the unit before it bursts into flames. I ordered a $50 replacement from Car Parts Wholesale on eBay which seems to be working great, so that's a nice way to save $200 compared to an OEM replacement. The job is pretty straightforward, it took me a few hours working at a leisurely pace. The hardest part is just getting everything out of the way in order to access the blower.

Parts Needed:
Blower Motor- 64 11 1 468 542
3/8" hose clamp for coolant overflow line
Zip ties

Step 1: Remove coolant expansion tank

If your coolant tank is at the back of your engine bay, you'll need to move it out of the way. You don't need to drain the tank and completely remove it, you just need to get it away from the firewall. There are two hoses and an electrical connector on top of the tank that will need to be disconnected. The coolant overflow line on the driver side is held on by a hose clamp, while the smaller air hose on the passenger side should just pull right off. After these are all detached, you can remove the two bolts holding the tank onto the firewall, and push the tank out of the way. I just rested it on top of the intake manifold, with a few paper towels underneath to catch any spilled coolant.



Step 2: Remove positive jumper terminal and diagnostic port

You'll have to take the plastic covers off of the jumper terminal, and unbolt it from the bracket it's mounted to. Then you can unbolt this bracket, and pull it off with the diagnostic port.



Step 3: Remove wiring harness cover
The wiring harness is attached to a cover with zipties- cut all of these zipties, and then unbolt both sides of the cover and remove it from the firewall. You may also need to remove a small throttle cable bracket on the driver side.



Step 4: Remove firewall panel

The firewall has a big removable panel covering the blower motor- this needs to be removed. It is held on by five bolts- one in each corner, and one on the bottom center.



Step 5: Remove plastic covers

There are two plastic covers in front of the blower motor- the large outer cover can be pulled right out. You may have to slightly bend the plastic to get it out, so do this carefully. After this is removed, you'll see the smaller inner cover which is held on by a plastic strap and two metal clips on the bottom corners. Unclip these, being careful not to lose them, and then unhook the strap. This strap is very tight, so you may need to use something like a screwdriver for extra leverage to pry it apart.



Step 6: Remove blower motor

Woohoo, you've finally found the blower motor! To get it out you need to unplug the two wires powering it, and then remove the metal strap holding it on. This can be tricky- you need to pull up on the bottom of the strap to release it. This works best if you have some sort of tool to pry with- I used a paint can opener to hook onto the strap. Once this is off you can go ahead and pull the blower motor out- I found it easiest to pull the passenger side out first, then rotate it upwards to get the driver side out.



Step 7: Install new blower motor

Put the new blower motor in the same way you took out the old one, strap it down, and plug it in. Make sure the blower is oriented properly and then hook the top of the strap in first, before pushing down on the bottom to lock it in. It's a good idea to turn your fan on and test the new blower to make sure it works right before covering everything back up- just make sure there's nothing in the way that will interfere with the fan blades.



Step 8: Put it all back together!

Installation is the reverse of removal. If your car is anything like mine there will be 20+ years of grime built up on all the parts you took out, so I'd recommend cleaning everything before you put it back in. Use new zipties to attach the wiring harness, and use a new hose clamp for the coolant overflow line. If all went well, you can now enjoy your car with a working blower!