Intermittent electrical fault

[tomson]

The car is a 1989 325i.

The problem is this, sometimes the wipers, indicaters, horn, map reading lights and brake lights dont work! Leave it for 5 mins and they all work fine! The head lights are fine on all settings when the others dont work as is everything else electrical inside the car. I'm going to have a look at this tomorrow, does anyone have any pointers of what to check? I'm guessing this is probably a loose/dodgy connection somewhere in the dash area?

[daimlerman]

From my fun and games with the folly this week,most of your list of items is in the loom that crosses the dash direct from the fuse box.So you are looking for issues in that area.I think that I would start with the connectors on the steering column,the ignition one must be favourite.Belive the maplight thingy has it's own terminal in the accesories socket,so that may be totaly seperate issue.I hate electrical problems,at least with an oil leak you can see the stuff!!

[zaust]

Have a look at the earth point's too. They can reak allsorts of havok.

[tomson]

Yes I totally agree!

I had thought what you suggest but I'm sure the headlight switch is part of that loom too and they work fine!
I know the map light mirror definately has its own loom to the accessory socket but it is a related fault.

[zaust]

And check the alt output as low voltage will also cause weird thing's to happen.

[tomson]

What should it be, 12v ? Sorry if its a daft question!

[daimlerman]

I have dip and main operating from my indicator stalk but no indicators or flash,and you think you have problems? Headlight switch and dash pushbuttons are a seperate loom that plugs into the L/H socket behind the glovebox,I hate wires,oil leaks etc etc....

[BadDave]

What should it be, 12v ? Sorry if its a daft question!

Approx 13.9V with the engine running at idle

[tomson]

Had a look at this earlier and the wiring behind the glove box as a total mess, looks like some fool has tried to fit a DIY alarm blindfolded!

The loom that runs across the dash for the instruments and all controls, is it seperate from the rest of the car loom, I cant remember?

Whilst fiddling around with the wires it cured this problem! V V V V V V

http://www.e30zone.net/modules.php?name ... 0&start=50

The car obviously has serious wiring issue's behind the dash and I'm wondering what to do about it

[Brianmoooore]

Bite the bullet, unplug the connector in the back corner of the glovebox, and take the whole dash out. You should be able to sort everything out then.

[daimlerman]

Two looms cross the dash,the one that plugs into the l/h (white) socket,feeds the push switchs,heater fan and lights and the main loom that exits from the fusebox and feeds the column controls and the white and blue cluster plugs.This last one has approx 60 wires in it.

[neilofla]

I had a similar problem some time ago - Indicators, horn, wipers and brake lights all ceased functioning at the same time, and all came back to life at the same time

Traced it to an 8 pin connector on the underside of the fusebox circuit board - the pin was seated fully home, but the wire in the pin was a bit loose. Took me a while to find it as every time I went looking for the problem I must have jostled the wire temporarily back into position - only for it to drop out again 2 weeks later!

If your wiring loom is a mess, then I guess the problem could be anywhere - but you might be lucky and it could be the same connector.

[neilofla]

Found the link to the wiring diagram I used:

http://m42club.com/reference/wiring_diagrams/04.pdf

Connector #114, pin 8 was my problem

links to more diagrams on http://www.m42club.com/forums/showthread.php?t=72

[BigBavarian]

That sounds exactly the same as my brothers 325 touring. The wipers, indicators and brake lights will stop working, tap on the relays in the fuse box and it all stars working again. Any ideas people. A bit annoying when its raining and the wipers pack in!

[Brianmoooore]

This plug often gets pulled partly off when the fusebox is opened up. It's essential to make sure it's fully home when you reassemble the box.

[neilofla]

That sounds exactly the same as my brothers 325 touring. The wipers, indicators and brake lights will stop working, tap on the relays in the fuse box and it all stars working again. Any ideas people. A bit annoying when its raining and the wipers pack in!

Disconnect battery, remove fusebox lid, remove all fuses and relays, (maybe no need for this but i did it to inspect all items) undo 3 or 4 screws, lift up circuit board carefully, undo 8-pin connector, and check how all wires are seated in their respective pins.

Just as easy at this stage to undo and redo all wires into all pins for peace of mind. Be sure to pull the connector square off - I don't know how much bending or twisting the board will take before cracking

Hardest bit is working while bending over the fusebox - theres little slack in the loom coming across the bulkhead/from dash.

Hope this helps the OP too

[BigBavarian]

Cheers i'll try that this week hopefully it'll do the trick and the car will be able to be driven in tha rain!

[tomson]

I had a similar problem some time ago - Indicators, horn, wipers and brake lights all ceased functioning at the same time, and all came back to life at the same time

Traced it to an 8 pin connector on the underside of the fusebox circuit board - the pin was seated fully home, but the wire in the pin was a bit loose. Took me a while to find it as every time I went looking for the problem I must have jostled the wire temporarily back into position - only for it to drop out again 2 weeks later!

If your wiring loom is a mess, then I guess the problem could be anywhere - but you might be lucky and it could be the same connector.

Excellent, I will have a look at this first as I dont really want to take the dash out if not necessary! I've discovered as bigbavarian says, if you "tap" the fuse box it can rectify the fault but only temporarily - most annoying if it's raining!

Thanks for the input guys, I will update this thread when I've had a look!

[neilofla]

tapping the fusebox lid initially worked for me - but as you say, only temporarily. I feared it was a cracked solder joint. Turned out to be a simple loose wire. Make sure you disconnect the WIRE and reconnect it to its receiving pin, not just push home the 8-pin connector onto the circuit board

from memory, I think there's one more common connection that links wipers+indicators+brake switch+horn to ignition - let us know how it goes with the fusebox side of things - I can dig out that diagram and post it up here if its needed

[tomson]

tapping the fusebox lid initially worked for me - but as you say, only temporarily. I feared it was a cracked solder joint. Turned out to be a simple loose wire. Make sure you disconnect the WIRE and reconnect it to its receiving pin, not just push home the 8-pin connector onto the circuit board

from memory, I think there's one more common connection that links wipers+indicators+brake switch+horn to ignition - let us know how it goes with the fusebox side of things - I can dig out that diagram and post it up here if its needed

Will do, can you remember what colour the offending wire is?

I'm fairly certain this is where the problem is coming from as I've discovered plugging and unplugging the wiper relay fixes the fault temporarily so it is pointing to this fusebox pin fault. I will have a proper look in the light over the weekend.....

[neilofla]

solid violet - as per the wiring diagram linked above

even though the diagram is for a US pre facelift 325e and mine is a UK 318is, that part of the loom seems to use the same wire colours - I guess yours should be the same too

[tomson]

Cheers