Electrical Advice Please

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tatkins101
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Sun Apr 14, 2019 7:22 pm

Hi,

Picked up my first E30 5 days ago, been 5 of the most enjoyable days since. BUT, there is clearly an electrical issue, advice on the following would be greatly appreciated.
1. Tacho/ Eco not working. Speedo Fuel and Temp all work fine but temp, eco and tacho have no backlighting.
2. Radio doesn't turn on.
3. Interior lights dont turn on
4. Central locking not functioning properly, can lock car fine from inside, key turns in door but doesn't lock.

I understand that electrical faults can be linked together, not sure if these are or are separate issues. Have replaced all necessary fuses but resolved nothing.

Ta :drive:
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Brianmoooore
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Sun Apr 14, 2019 9:45 pm

Fairly confident these are all unrelated issues.

1/ There are two lamps that illuminate the cluster, via plastic light guides. These are in the two larger holders on the back of the cluster, and one of the lamps has failed. They are 3W 12V capless, which must be used - not the more readily available 5W 12V ones. If you use 5W, things WILL melt.

Although the tacho and Eco share the same housing, they are completely separate gauges. No common fault that affects both of them, so I'd start by checking all is well with the pins and socket that plug the assembly into the main circuit board.

2/ This could be anything. Wouldn't be the first that I've seen where the radio has had no connections to it at all, and is just filling up the gap in the dash. A radio should be connected to a four wire loom that plugs into the accessories socket behind the glovebox area, but your car is likely to have had a few aftermarket installs since it was new, and they could be wired in any one of several dubious ways. You'll have to pull the radio out, and see what sort of mess is behind it.

3/ Don't light at all, or don't light when the front doors are open? There's a three position switch on each light - permanently on, permanently off, switch by doors. Check the switch position (and whether there are lamps fitted.)

4/Do you mean that the car unlocks from outside the car but doesn't lock? Does this happen with both doors and the boot? If you lock/unlock a door from the inside, does this lock/unlock the other doors and boot as well?
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tatkins101
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Mon Apr 15, 2019 9:33 am

Thanks for the reply.

Sorry I wasn't totally clear, the Tacho/ Eco do not work at all, not just the lighting issue. I have researched it a bit and SI batteries seem to be the issue.
Regarding the radio what should I be looking for when taking it apart? Damage to the loom? connection issues? anything else?
The door locks all lock from the inside, but cannot lock from outside the car so I dare not lock it and close the doors. Not sure if this is electrical or mechanical.

Ta
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Brianmoooore
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Mon Apr 15, 2019 7:18 pm

SI board batteries readily affect the tacho. (and temp.gauge), but not usually the eco. gauge, unless the problem is that the batteries have leaked corrosive juice over the SI board onto the eco. gauge circuitry nearby. If the batteries are dead, you should have issues with the SI LED display as well.
If the radio is anything other than the one fitted from new, then any conceivable type of bodge up could be behind it. An observation of the general standard of the work would be a starting point.
Not all E30s had central locking, but assuming yours has, then what you say is common when the electric locking fails. The locks should work mechanically, but after 30 years of not being lubricated and being normally assisted by motors, they become to stiff to work from the key without that assistance.
Remove the panel in front of the 'speaker in the driver's foot well, remove the 'speaker, the little plastic piece below it inside the sill, the two cross head screws directly below the 'speaker, and lift out the locking ECU, complete with its mounting bracket, from its hiding place deep inside the sill. Unplug the locking ECU and connect a 12 volt lamp of at least 5W between the brown wire and the red/black wire, and see if it light at full brightness.
Don't put it all back together before reporting back.
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tatkins101
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Wed Apr 24, 2019 4:57 pm

Thanks for the response and sorry for the slow reply.

I took off the lower part of the dash for ease of access and immediately found a plug hanging there disconnected. Three wires, solid brown, blue/brown, and white/red. What would this be for/ is it central locking related.
tatkins101
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Wed Apr 24, 2019 6:11 pm

Also fixed the radio/Tacho not working, was the boot open sensor shorting blowing the fuse, disconnected it and voila.

Did a bit more fiddling with the locks, turns out the car can be locked from the outside but I have to turn the key very very hard. How would you recommend fixing the stiffness to the locks?
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Brianmoooore
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Wed Apr 24, 2019 6:16 pm

Definitely nothing to do with the central locking.
Going by where you say you found it, it sounds like the plug for a gong that should be mounted in the panel you took off. This is part of the on board computer option, which replaces the analogue clock, but the wires should be red/white, brown, and black/brown, although there were some colour differences on the early version of it.
Edit: I've found a US circuit diagram which shows the gong control wire as blue/brown.
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Brianmoooore
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Wed Apr 24, 2019 6:34 pm

All that will happen if the 'boot open sensor' (pin switch) short circuits is that the boot light will stay on. The problem you have is the common one of the supply wire to the boot light (red/green) chaffing on the boot hinge and shorting to the bodywork. This will blow fuse 21, which also supplies the radio memory, the interior lights, the clock, the glove box light on early models, and charges/maintains the SI board batteries in the instrument cluster.
The supply from fuse 21 does not directly affect the tacho, but the tacho. does stop if these batteries fail, so I suggest you add checking these batteries to the 'to do' list, since if they start leaking, they will write off the entire electronics of the cluster.
To sort the mechanical operation of the locks, you need to remove the door cards and carefully lubricate every joint and lever. There is also an alloy L shaped piece on the end of the driver's door lock barrel, which will need replacing if it is badly worn.
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tatkins101
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Wed Apr 24, 2019 6:46 pm

I'll add the batteries to the list, can do this at the same time as replacing the backlighting bulbs for the cluster. I'll attack the locks tomorrow and update afterwards.

Thanks very much for the help :cool:
tatkins101
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Thu Apr 25, 2019 10:44 am

Removed the door cards to find I have no access to back of locks. No hole in door to access them? Very strange design...can't think of any easy way to access locks without cutting away at the door. Any ideas?
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BenHar
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Thu Apr 25, 2019 3:37 pm

There is a good page about it here: http://www.billswebspace.com/BMWE30Door ... ebuild.htm

Ben
tatkins101
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Thu Apr 25, 2019 5:30 pm

I saw that page earlier, I don't have that rectangular hole level with the lock itself. Managed to free the lock up significantly with some WD40 and gentle persuasion. Not fully resolved but definitely an improvement.

Now the next thing... :mad:

Both rear windows do not work. Haven't looked into it at all yet so where would be a good place to start troubleshooting?

Ta
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Brianmoooore
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Thu Apr 25, 2019 5:36 pm

It will make giving advice easier if you tell us exactly what model and age of E30 this is, since there are detail differences between models!
Rear windows electric or manual?
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tatkins101
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Thu Apr 25, 2019 5:39 pm

Its a 89 325i SE 4 Door, with electric windows all round.
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Brianmoooore
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Thu Apr 25, 2019 6:04 pm

Lovely choice of E30 - always preferred a 4 door saloon to a 2 door. The doors on a 4 door are much more 'in balance' with the rest of the shell.
Rear electric windows require both the switch on the rear door card and the one in the centre console to be in working order for the windows to work.
Do they not work from either switch? There's a square isolator switch on the front of the centre console that switches off operation from the door card switches.

You can still flip off the large C clip through the smaller holes on a front door from a 4 door, and extract the lock. Remove the window winder mech. if you want better access. Use a wooden wedge between the weather seal and the glass to keep it in place, undo the four(?) bolts holding the mech., unhook it from the glass and remove it. Easier if you leave the electrics connected, and 'lower' the window as you unhook it.
All things are easy on an E30 if you know the procedure.
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tatkins101
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Thu Apr 25, 2019 6:28 pm

Ah thank you! i agree with the balance of the doors, just looks right to the eye.

Both the doors do not work from either switch, and isolator has no effect (Always wondered what that button was for :| )

Thanks for the advice on the locks, will have to have another go. When testing the locks I became a bit baffled as the two keys the car came with have different capabilities, the larger key fob with the LED built in, is a lot more worn down and works the door locks but not the ignition. The secondary key has all its groves intact does not unlock/lock the car but does turn the ignition on. Confused.com to say the least...
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Brianmoooore
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Thu Apr 25, 2019 7:28 pm

Short answer is that there is no single common problem that affects both rear electric windows. The rear doors don't normally get used enough to get problems with the wires from the B pillar to the door, and the plug and socket for the loom is in the warm and dry inside the B pillar.
Are you any good with circuit diagrams? http://www.autolib.diakom.ru/CAR/BMW/19 ... /fig10.pdf This is the diagram for the windows (and, as a bonus, the central locking) The diagram shows the paths through the switches when they are at rest, so you can check if power is getting to where it should, and should not, with a test lamp.
It looks like either the driver's door lock or the ignition barrel has been changed at some time, without bothering to code it to the original key. Try both keys in the boot lock and the passenger door lock, to see which one fits.
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ChrisHC
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Thu Apr 25, 2019 11:52 pm

The page given earlier shows how to rebuild the door lock using the rebuild kit available from BMW. That kit contains a full set of tumblers so that you could change the door lock to operate with the same key as the ignition, but it will require a bit of trial and error to get the correct tumblers. The kit also provides the alloy L shaped piece Brian referred to as possibly being worn.
tatkins101
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Sat Apr 27, 2019 8:40 pm

Thank you both. Will look into it further and get back when i've hopefully cracked it.
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