BMW E46 Final Stage Resistor Unit

Decided that with the weather being so pleasant, I could take a portion of the afternoon to work on my car. The blower motor had stopped blowing, and I knew that the final stage resistor (still original to the car for all I know) might finally have gone out. I’d located the APSX FSU that I bought years back amongst my spare parts.

Getting to the FSR was easy. By now I’ve done this more times than I care to mention. I found the FSR harness difficult to unplug from the FSR. Closer examination revealed that the wires going into the harness were discolored. Fortunately, I was able to separate the harness from the FSR. I noted that the harness had melted somewhat.

After scraping at the harness with a small flathead screwdriver, I plugged it back into the old FSR. The blower motor came back to life. Plugged into the APSX FSU, blower motor unresponsive. Conclusion: APSX FSU must be defective.

I conducted a quick search to see if anyone else had encountered a melted FSR harness, and turned up a number of interesting forum threads relating to the FSR. This one in particular piqued my interest: failed blower resistor (final stage resistor) not really dead | Bimmerfest

What I gather is that the FSR has been through a number of revisions over the years.

One obvious change is the heatsink design. Updated part numbers have a larger number of fins (prongs), increasing the surface area.

Additionally, the potting material has changed from a hard epoxy resin to a silicone.

Chattering sounds and camber plates

I’ve just gotten through swapping sway bar end links and a tie rod assembly.

I was so certain that the sounds I was hearing from the front end were due to the sway bar end links. They failed visual inspection — the boots were clearly torn.

The new Lemforder sway bar end links went on fine, and I got them on quite tight.

I drove over to the shop to get an alignment done, and the front end chattered as it went over bumps in the road surface, which can be indicative of any number of issues, but I’ve got the SPC caster/camber plates on as well.

I looked up SPC camber plates and was pleased to find that they’re used in a range of applications, which means I’ll have an easier time finding other cases to review.

I’m really hoping that it’s not the camber plates that are causing this new noise. Without them, I’d still be up against one degree of cross-caster. My gut tells me that it might be them – I read about the springs doing something with the spring perch. Going to have to investigate this further.

On second thought, the greatest probability should be assigned to the event that there is something that hasn’t been torqued down enough. Given that I don’t have the BMW special tool to torque down the front upper strut nut, this nut should be most suspect.

In the past, I would have used an impact wrench, but I learned from my mistakes.