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Dead FET Power Transistors

I am trying to find a component part number or a schematic for a Blower Control Board for a 1989 BMW with a 535i engine. The board has the number

275 526. L 06 stamped on it, and the Control Assembly has the name BEHR and the numbers 90 . 947 . 00 . 842, E 3264/11 and 1 388 629 . 2 stamped on it. There are four (4) blower motor settings on the control switch and only one (1) works...High Speed! Anyone that can let me know where to find the replacement FET transistors on the board would be of tremendous help. The four (4) FET's are all the same. I have looked at the transistors under a magnifying glass and can find no numbers stamped on them. I do not know if they are made by an European Manufacturer or not. I also do not know whether the FET's or N or P type or MOSFET's, etc. Any help as to the source of this information would be very appreciated. Thanks!
Reply to
Robert L. Milton, Sr.
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The FET is a type N 60V 14A - BUZ 71S3 but you can replace for th regular BUZ 71 (the diference is instead of 60V is 50V)

The IC is a LN2903 - Dual differential comparator

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pboavida
Reply to
pboavida

How do you know the FETs are bad? Did they explode?

FETs tend to fail shorted, so the more likely symptom of a bad FET would be that the fan runs at nearly top speed on all settings.

I'd go check out the on-line junkyards if you can lower yourself to do so.

Reply to
Ancient_Hacker

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