Heater fan relay location, and assorted other questions as they come...

[FredDeuel]

My heater fan quit working a few weeks ago on my 1986 635csi, and as this is the first day it's been 40 degrees and I've been free since then I'm trying to fix it (or at least narrow down what needs to be done). I've been using this thread on Bigcoupe to try and find my problem: http://bigcoupe.com/phpBB2/viewtopic.php?t=14791&

What works and what doesn't (as per the thread mentioned above):
-AC works on high, but not anything else. AC blower transistor is bad (where is that and what does it look like?)
-Heater fan does not work at all. Either the fan motor or select relay is bad.

As I have a spare relay for the heater fan I am going to test that first to see if I need a new motor or not.

I've dropped the glove box but am not sure where the heater select relay is, if anyone has a picture or diagram of where these are located it would be greatly appreciated.

[CW6er]

Are you sure you have a correct replacement for the blower select relay? It is not the same as the Main relay but the High Beam (K3) can be used:

Quote from relay info here:
http://bigcoupe.com/phpBB2/viewtopic.php?t=16409

High-Beam Headlamp (K3), and Blower Select relay in the Center Console:
5 prong change over relay (the output changes between pins 87 and 87a as relay operates) - Bosch 0 332 204 401 - Also a 25x25mm metal can, usually with a purple strip across the top. (Do not confuse it with the 5 prong Main Relay with pins 87 and 87b, See above).
______

This shows the blower select relay and removing the transistor plate. I wouldn't mess with the impact switch, but if you do, disconnect the battery first or you can burn it out:
http://www.malloc.nl/BMW/635CSi/page....html#refertoc

Here is removing and repairing the heater blower, Same transistor and technique is use to repair the A/C blower transistor:
http://www.normgrills.net/bcg/Blower_Transistor.htm

Pull the Heater Blower motor and test it with 12v on the bench.

[team2win]

Are you sure you have a correct replacement for the blower select relay? It is not the same as the Main relay but the High Beam (K3) can be used:

Quote from relay info here:
http://bigcoupe.com/phpBB2/viewtopic.php?t=16409

High-Beam Headlamp (K3), and Blower Select relay in the Center Console:
5 prong change over relay (the output changes between pins 87 and 87a as relay operates) - Bosch 0 332 204 401 - Also a 25x25mm metal can, usually with a purple strip across the top. (Do not confuse it with the 5 prong Main Relay with pins 87 and 87b, See above).
______

This shows the blower select relay and removing the transistor plate. I wouldn't mess with the impact switch, but if you do, disconnect the battery first or you can burn it out:
http://www.malloc.nl/BMW/635CSi/page....html#refertoc

Here is removing and repairing the heater blower, Same transistor and technique is use to repair the A/C blower transistor:
http://www.normgrills.net/bcg/Blower_Transistor.htm

Pull the Heater Blower motor and test it with 12v on the bench.

Chris, I was curious as to the relay in the glovebox.. I have an 84' 633 and I had to look, I don't see any relay behind the dash, or up near the ecu, nothing... is this for certain years???

[FredDeuel]

It's the exact same relay, and it's behind the climate controls, more than a little difficult to get to if you're hands are a little big. I got the fan working, turns out the clasp for the motor had came undone allowing the motor and impellers to move forward and bind against the ducting. I oiled the motor a little and put it back in place. I still need to replace the blower speed control transistor.