BMW Relay Data

Ohmess

Ohmess

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Hi All -- I am adding some electrical capability to my coupe, and purchased off ebay an electrical fuse box module from an e39 BMW. The module came with two eight circuit fuse blocks, with three separate 4 circuit power distribution setups, three relays with sockets and a separate 40 amp fuse. All the wires have about 12" pigtails. Needless to say, for $25 I now have more than enough capacity to add whatever I might want to add to the coupe.

I want to use the relays, but need to understand their electrical properties, particularly their maximum load, before I do so. I believe BMW has for years color coded their relays based on the properties of each relay. The relays in question are light green and dark green.

Does anyone know of a reference source for BMW relays? I have found several places that say if you are seeking an e28 wiper relay, it is orange. This is lovely, but I want to know about using the relays to power a particular non-oem fuel pump, etc.
 
The colors likely have to do with the function and internals of each particular relay. F'rinstance, although on my E36 'vert the relays would interchange, they wouldn't necessarily function when swapped around (some do, some don't).

IIRC a Bentley manual doesn't reveal what you're looking for. Best bet might be to refer to the ETK or fiche for which relays have which function.

Generally, relay pins are numbered 85, 86, 87 and 30. Pin 30 is the hot line carrying power, one of the others carries the signal from the switch to the solenoid, one grounds the solenoid, causing power from 30 to be connected to the load. Since I haven't had to mess with these things lately I can't clearly remember which is which except for 30.

If you see a duplicate pin like 85a, it's probably just a second connection to 85, or whichever.

Sometimes the schematic for the internals is printed on the side of the relay, or maybe they only used to be.
 
If you search the E24 Bimmerforum, somewhere is a complete tutorial on relays plus which current relays can be used to replace older relays.
 
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Here's a schematic representation of the E24 relays. Note that some have built-in noise suppression, some have diodes to make them polarity sensitive, some are normally closed, some are normally open, and some have double poles.

http://www.realoem.com/bmw/showparts.do?model=5374&mospid=47205&btnr=12_0347&hg=12&fg=35
 
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