Weird electrical problems...

Mon Jul 17, 2006 1:17 pm

Hello!

I've just had an m20 2.5 fitted into my little 316... Since this has been done there are 1 or 2 little annoyances, which I hope someone may be able to solve...

1) Electric windows now only work when door is open. Even when driving... They used to work fine, so I'm guessing it is something to do with the loom.

2) Heater blower no longer works on any speed. Again, used to work fine before.

3) Electric mirrors no longer work. Again, fine before.

As I said, I'm guessing this all has something to do with the new loom, but as I know nothing about these things, I'm hoping someone can shed some light.

I have checked the fuses in the fuse box, and they are all ok... Is there another secret hidden fuse box anywhere? (my old e34 had one under the rear bench as well...)

Thanks in advance for your help!

Mon Jul 17, 2006 1:23 pm

its an eath fault my friend i had the same problem it is k7 relay.
There is a earth on the stater eath this to the earthing point on under the inlet manifold side of the engine bay and it should work. ,i am sure
Brian will be on later and confirm

Mon Jul 17, 2006 1:34 pm

Thanks for your swift reply!

So there is an earthing strap which needs to be connected from the starter? Or I need to make one?

Apparently, the windows did the same thing in the car the engine came from... I'm not sure about the mirrors/heater fan...

Mon Jul 17, 2006 2:09 pm

there are two small spade type connectors on the starter the are both earths i think and what happens they recieve a +12v supply on starting.
They usually earth through the starter but the eath through the starter fails thus causing your problems. eg mirror blah blah
you will need to eath one of these out so K7will energise when the engine is running.
send me your email address and i will send you some wiring diagrams for the circuit in question
and all wil become clear
regards
Ben

Mon Jul 17, 2006 2:10 pm

or bolt on the later engines sorry for got to mention that are near the south east ??

Mon Jul 17, 2006 2:37 pm

Hi mate,

My email address is carl.bimmerman@gmail.com

So I need to make an earth from either of the spade connectors on the starter, right?
My car is the facelift model, but I have fitted a pre facelift engine... is this gonna make any difference?

Mon Jul 17, 2006 3:53 pm

no it should not make any difference as i had a an 87 engine in my post facelift convertible this is what you need to do take top spade conector and place it on the body start the car up and check everything works and then make some kind of permemnt conection as the earth casin on the starter is knackered . will send tose diagrams ina min fella
regards
Ben

Mon Jul 17, 2006 6:03 pm

Got the email thanks, Ben.

I'm no sparkie though, so am struggling to understand the diagrams. I'm gonna just go and have a look at the starter in a minute, see is I can do what you suggested...
One quick question - where is this k7 relay? in the fuse box, or hidden somewhere else??

Mon Jul 17, 2006 9:47 pm

Sorry to hi-jack the post but I seem to have a related issue in my '89 320 tourer.
Fuse 10 keeps blows several times a week and when it does it takes out the heater, electric mirrors, windows and sunroof. Looks like the issues might have something in common.

Even stranger is if Fuse 10 blows while you are driving and you have the lights on dipped beam, they dont turn off after you switch off the lights, while the engine is running. This does seem really odd!

For some reason it looks like my K4 relay is energised when Fuse 10 blows.

Any ideas on whether this is also an earthing problem or something completely different would be great,

Thanks,
Sharknose

Mon Jul 17, 2006 9:58 pm

Unloader relays are K5 (widows and roof) and K7 (mirrors and fan) and are both in the main fusebox. Positions should be marked on the lid.
One end of the coils (pin 86 ) of both these relays is connected to 12V+ when the ignition is on. The other end of the coils (85) are connected together, and go by a black green wire to pin 15 of the C101 engine loom socket on the bulkhead.
A black/green wire in the engine loom then goes to the smallest terminal on the starter motor. This terminal is connected to the winding of the starter motor, the other end of which is connected to earth, via the starter motor body.
Because of the low resistance of these windings, as far as the relays are concerned, this terminal is earth.
When the starter motor is engaged, this terminal becomes 12V+, and so, relays K5 and K7 have 12V+ on both ends of their coils, and drop out, disconnecting windows, roof, heater fan and mirrors while the starter is operating.

Tue Jul 18, 2006 8:24 am

excatly what i was trying to say but english is crap dyslexic git here

Tue Jul 18, 2006 8:55 am

Sharknose3 wrote:Sorry to hi-jack the post but I seem to have a related issue in my '89 320 tourer.
Fuse 10 keeps blows several times a week and when it does it takes out the heater, electric mirrors, windows and sunroof. Looks like the issues might have something in common.

Even stranger is if Fuse 10 blows while you are driving and you have the lights on dipped beam, they dont turn off after you switch off the lights, while the engine is running. This does seem really odd!

For some reason it looks like my K4 relay is energised when Fuse 10 blows.

Any ideas on whether this is also an earthing problem or something completely different would be great,

Thanks,
Sharknose

Pull up the gearlever gaiter and find a white two pin plug and socket sitting down by the bottom of the gearlever on the right hand side.
Pull it apart, and see if that cures the fuse blowing. You will have disconnected your reversing lights, so they won't work.
The problem is most likely damage to the reverse light switch wiring under the car.
As for your other problems - sort the fuse blowing first, and see if they go away.

Tue Jul 18, 2006 9:39 am

Thanks Brian, will give it a go

Tue Jul 18, 2006 9:59 am

Just to confirm the above, I had a similar problem while driving on the A1(m) electric windows, heater, mirrors, all stopped working. It turned out my starter motor had burnt out. New starter motor, now no problems.

All the best.