Paging JB - BMW 5 Series electrics problem.

My housemate has a 1992 J plate E32 525i Sport and I've just freed off
the seized drivers door lock only to find a few electrical problems now
it's all back together again.

Everything apart from the actual door lock itself was working fine
before, but now the wipers only work on their fastest speed, the
elctric windows have packed up and the central locking has gone awol
too[1]. There may be more faults but I ran away to get your expert help
when I noticed just these few problems. Any clues?

I did have to remake the connections on the deadlock microswitch as a
wire was broken right up by the plug, I think the window had been
catching it after someone else fitted a new winder motor. I've checked
all fuses and everything looks ok there, do these things have a central
control box for all these functions?


[1] Which is a bind because the fuel filler flap is controlled by it
too. I've overcome that by pulling the actuating rod out from inside
the boot

 

First off, what's the battery voltage like? If it's not tiptop, it can cause
all sorts of grief, especially with the numerous control modules all over
the fucking place (especially the central locking module!). I'm very
confused as to what happened to the wipers though. You didn't delve into the
steering column wiring did you?
The microswitches are a pig if they give trouble. I had a problem with two
cars which was only 'cured' by bending/adjusting the actuating rods for the
door locks until they just 'worked'. No science there at all. Just bend and
try till it works. The deadlock microswitch is linked to the window motor
control module too. Hold the key in the deadlock position for >3secs and it
should wind up all of the windows on some models.

First 'mod' I carried out on my last 2 E34s too.

Have a shuftie over on alt.autos.bmw or the Bimmerforum or even www.E34.net
for more help.

JB

JB

 

I will check this tomorrow morning. I believe the control module for
the CDL is under the rear seat. I'm wondering if there is a module that
is common to all these things that have gone wrong?

Nope, only went into the driver's door to sort a seized door lock that
wouldn't turn on the key. I removed the handle/lock assy and cleaned it
up so the key would turn the lock then reassembled it back into the
door. Since then it's started playing up. The microswitch on the top of
the door handle mech has been disconnected for a while, but that never
stopped the CDL working before. While I was in there I remade the
connections on the yellow plug as one was ripped out when it went back
in. It now has bullet connectors, but there is no voltage there, and
there was before I took it apart.

What is that electrical bit that goes around the keylock, it looks like
a horseshoe shaped tube with a cable on each end?

Sometimes I get a slight buzz from the passenger side CDL motor when I
operate the button atop the door, but it's not happening all the time.

Luckily the windows are all at the top of their travel, but the
driver's one does go a little high and pushes the panel out slightly. I
think the limit switch needs adjusting.

It worked before, but at least he can fill it up now.

Thanks hugely, I'll pop over and see if anyone there has more ideas.

 

Try isolating that circuit again. Someone possibly cut the wire as there is
some sort of current leakage that upsets the control circuitry.

Heater coil?

 

Having done some more research, it now looks likely that either the
control module or fusible link on the battery under the rear seat are
to blame. Some owners have reported similar or exactly the same faults
and they have been traced back to these two things. After chatting on
facebook tonight, one of my 'lady friends', who also has a similar aged
535i, says her car does this intermittently, so her husband will be
checking it out for her tomorrow. There is also a 30A fuse in the
vicinity that needs a poking at.

I think you might be right, It seems that it has heated door locks as
well.