m50 sticky fan relay?

Need technical Q/A then you're in the right place

Moderator: martauto

JF008
E30 Zone Regular
E30 Zone Regular
Posts: 631
Joined: Tue Jan 17, 2012 11:00 pm
Location: Fort McMurray

Post Sun Feb 23, 2014 6:14 pm

Hi there, the electric fan stays on sometimes 20-30 minutes (or however long it takes me to realize) after cutting the ignition. Only happens when the engine is warm as the fan kicks in at the right time e.g. when stopped in traffic or after cutting the ignition.

It bothers me the fan stays on for so long as I suspect it caused me a flat battery no so long ago! All I can think of is a problem with the relay as its an intermittent problem. The thing is I looked up the part number and it does not specify anything. Which relay should be used? Thats mine at the moment:

Image

I tried other coloured relays with no success...

Thanks

JF
User avatar
Brianmoooore
E30 Zone Team Member
E30 Zone Team Member
Posts: 49360
Joined: Mon Jan 10, 2005 11:00 pm

Post Sun Feb 23, 2014 8:43 pm

Is this standard E30 (replicated or OE) air con fan wiring and thermoswitch?
JF008
E30 Zone Regular
E30 Zone Regular
Posts: 631
Joined: Tue Jan 17, 2012 11:00 pm
Location: Fort McMurray

Post Sun Feb 23, 2014 9:44 pm

Brianmoooore wrote:Is this standard E30 (replicated or OE) air con fan wiring and thermoswitch?
Hi Brian thanks for your reply, not sure about the wiring, I'm using an e36 air con rad with 80/88 (I think) temp switch. The wires from the temp switch and the fan seem to converge into a ''floating'' relay socket.
User avatar
Brianmoooore
E30 Zone Team Member
E30 Zone Team Member
Posts: 49360
Joined: Mon Jan 10, 2005 11:00 pm

Post Sun Feb 23, 2014 9:59 pm

The standard wiring feeds the relay control circuit from an ignition switched source, so if the fan comes on with that, it can only be the relay that's faulty.
Sounds like yours might have a permanent live control circuit, which could do with modifying to switched live.
JF008
E30 Zone Regular
E30 Zone Regular
Posts: 631
Joined: Tue Jan 17, 2012 11:00 pm
Location: Fort McMurray

Post Sun Feb 23, 2014 10:18 pm

Would you have an idea which relay is appropriate to the application? I don't want to risk having the fan not coming on at all or running continuously when I'm driving, regardless of the ignition source :D
User avatar
Brianmoooore
E30 Zone Team Member
E30 Zone Team Member
Posts: 49360
Joined: Mon Jan 10, 2005 11:00 pm

Post Sun Feb 23, 2014 10:28 pm

Relay required is a bog standard 30A four pin one, such as the orange ones in the fusebox. I don't know what exactly your purple one is, but it doesn't require five pins.
JF008
E30 Zone Regular
E30 Zone Regular
Posts: 631
Joined: Tue Jan 17, 2012 11:00 pm
Location: Fort McMurray

Post Mon Feb 24, 2014 8:11 am

Cheers Brian
User avatar
Brianmoooore
E30 Zone Team Member
E30 Zone Team Member
Posts: 49360
Joined: Mon Jan 10, 2005 11:00 pm

Post Mon Feb 24, 2014 9:36 am

Best solution would be to use the relay and fuse positions provided by BMW in the fusebox, and make up looms to suit.