aircon control unit

have a prob with intermittant working, one minute its on and all seems ok (heater fan, all aircon buttons, rear screen etc. all working then next second its dead. taken it out to see if loose connection, no. Been into
Bimmer spares dealer to get a new unit and was fobbed off with it has to be fitted by a garage with "all the right equipment" as uit has to be coded, not being a car techi no idea what they are on about, to me it looks like it just bolts on.... am i being blinded by science???
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What year and model?
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Blake Dodson wrote:

Check the final stage resistor unit. It is a bit expensive but very easy to replace on many models.
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Wouldn't make the control panel go dead, though.
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Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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318tdi 1998 diesel
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This is a very common problem on late model E36s. It's not that hard to fix the circuit board, there's a web page that shows you how. Sadly I didn't bookmark it.
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Sounds like BS to me. I swapped a AC control unit on a 735i with one from my old car (long story) and it was a doddle even for a relatively unskilled DIY'er like me.
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Dunno. Certain types have a memory which distinguishes which key is used at the time - a sort of him and hers thing. It's possible the software has to be loaded in.
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Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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all sorted now, although not a car techi i removed the unit and replaced with a new one, the unit cost 228, phew.... got 38 px for the old one so they'll replace a circuit board in that and put it back on the shelf, what a ripoff. The biggest laugh of all was when i went onto the BMW dealers parts department, the total lack of help and indifference was astounding, together with the sharp intakes of breath that i had the audacity to do summat myself and constant reminders that it "needs coding in" and the "right equipment" to carry out such a high tech operation, took me all of 5 mins to do and runs perfectly. Bet they would have charged me 500 quid to supply and fit too!!!
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