Xoutpost.com - climate control shutting off on its own

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I would suspect the FSR as well... how do you it was replaced? do you have a reciept, or you know it from the verbal from the seller? the reason i say so, if it was verbal, you can't be sure that it really was replaced... unless, it was your uncle who sold the car to you, or maybe a gift from mom-in-law... lol.. just kidding...

Look into FSR, do some research on it... that seems first possible option for the problem...

Quote:

Originally Posted by x5Alpine (Post 924145)

Yea, the control panel completely shuts off but the fan is usually still runnning

As the others have mentioned...it's pointing towards the FSU/FSR (final stage unit/final stage resistor) as being the culprit. I mention both names because it gets referred to as both...but I think the official nomenclature is final stage unit.

When it goes (the FSU/FSR), you generally lose control of blower speed and the ability to control it using the IHKA control panel. It can even turn itself on & off after you've shut down the engine...many times draining the battery dead.

Again, there is lots of info on FSU/ FSR issue on the e39 forums...and the e53 uses the same HVAC system (for the most part) as the e39 and uses the same FSU/FSR.

If the FSU was changed...make sure that they installed the upgraded one that has way more heat sinks (like approx 40). The old faulty ones, only have approx 12 heat sinks...the new/upgraded ones look like the one below. And if you read the MANY e39 threads on this topic...you should run across a list of brand names to avoid...some replacements have a high failure rate:

http://image.made-in-china.com/2f0j0...116923204-.jpg

Ok, thanks!!... Where is this unit located?

under the glovebox/passenger footwell IIRC

Quote:

Originally Posted by x5Alpine (Post 924178)

Ok, thanks!!... Where is this unit located?

As previously mentioned...this is a common and well documented DIY. If you type "bmw e53 FSU replacement" in a google or bing search box...you'll get a page of DIYs from the many BMW e53 forums, probably some e39 forums, and some videos up on YouTube.

Old style vs New Style

http://i34.photobucket.com/albums/d1...i/misc/FSU.jpg

(below is my old FSU from my 540iT...now taking up duty as a conversation piece on my desk)

http://www.bimmerfest.com/forums/att...8&d=1304720674

we have been quite the productive problem solving crew today haha!

:) Yes, we have...but before we give out too many "pats-on-the-back"...lets wait for the resolution post. I'd hate to eat crow in that the problem turns out to be a faulty IHKA. :(

Quote:

Originally Posted by Qsilver7 (Post 924202)

:) Yes, we have...but before we give out too many "pats-on-the-back"...lets wait for the resolution post. I'd hate to eat crow in that the problem turns out to be a faulty IHKA. :(

crossing my fingers its not!

So this is probably the culprit to why the climate control shuts itself off and on?

I don't think so. Shutting on and off doesn't fit the FSR. I'd pull the ihka. Super easy, take out radio pop out ihka. Check wiring. Also, pull apart and clean ambient temp sensor.