540i Blower Resistor

[Clarksonvalley]

I have been experiencing 'electrical burning smells' for a couple of years on any HVAC fan speed except full speed, so I finally decided it was the blower resistor - part no. 64 11 1 468 524 for my car. The Bentley manual wiring diagram says the blower resistor is located on the 'left side of the right foot well'. Wrong - it is located on the 'right side of the left foot well'. Getting the old one out and the new one in was a pain. You can barely see it from deep inside the left foot well - the resistor has a blue plastic case - the blue color will help you see it amid all the other stuff in the area. There are two plastic tabs - one on each side of the resistor that you need to squeeze to remove the it and a 4-wire plug that you need to remove from the resistor. You will need to remove the 'Trim Panel Foot Control' panel - part no. 51 45 1 978 935 to get close to the resistor. This panel is some sort of plastic and cracks very easily. This panel has a HVAC duct mounted on top of it and supplies air to the driver's side foot well and is a $131 piece that I will do without - I will try to repair my broken panel. After replacing the resistor, the smell is no longer present. This resistor mounts within the HVAC system air stream - the air flow evidently keeps the resistors cool, but it collects dust and crud over the years so I guess this accumulation of stuff contributes to the burning smell. Every time I repair something, a piece of plastic crap crumbles - hate plastic crap.

Tom
95 540i

[632 Regal]

Thanks Tom, copied to the electronics archive.

[shogun]

The trim panel you can repair DIY, use some fibre mat repair kit and add the mats to the back of the cover. $131 is on the high side for that trim panel foor control, black 51451978935 , for example ECS is selling a new one for $114.60
https://www.ecstuning.com/b-genuine-bmw-parts/trim-panelschwarz/51451978935/
or get a used one from someone who is parting an E34.

[bennyg]

I don't remember it being that much of a pain when I did it a couple of years ago. Symptom, no fan at speeds 1 2 or 3 (i.e. it was either off or full blast on 4). $40 odd AU off fleabay incl postage.

There's a screw that secures the trim panel that may be buried in carpet and hard to see. The hardest bit is finding the hole for the screw when putting it back in as there's nothing to line up the trim with, since it overlaps on all sides

Sent from my Redmi Note 3 using Tapatalk

[genphreak]

I'm well used to it and don't find it painful. Like everything on a BMW, you need to know how it went together to take it apart (gnnn)

Tip: There is light at the end of the tunnel, after years of breaking things it actually becomes a n endearing quality. Until you break the next part in an endeavour to repair something new or that you've forgotten about!

The problem I have is that everything is too damn happy in situ after 20 years. The line between breaking parts like the fan resistor out of their hole and breaking something is quite fine, especially when trying to keep the retaining clips relieved whilst you lie upside down breaking your lower spine with your arm cramping in a vain attempt to pull it out the required angle!

@ClasrksonValley; Nicely written piece, thank you. I've often been confused reading the Bently, but am used to as I only work on RHD cars, a lot of these things are reversed so I'm too used to looking on both sides...