Dodgy Wire

[v8s4me]

"Only one?" I hear you say.

I have several but this post concerns a dodgy looking wire coming off the top right of the fuse-board. It is un-fused, permanently live and goes through the bulkhead and disappears up behind the volt meter near the "no charge" light.

Before I disconnect it and see what stops working, does anyone have anything similar?

Incidentally, the "no charge" light has stopped working. I can't see the back of it so someone tell me what the colour coding is for the wires to this light and where they originate please?

[RCK974X]

The courtesy lights at each door are permanently live - I can't remember if mine were after a fuse or not, but they were routed to top with all the other wires for lights and gauges, and the passenger one has wires going over the top of the glovebox, so could be that.

[v8s4me]

No, they all seem to be working fine. But thanks for the suggestion.

[RCK974X]

I thought the 'no charge' light was connected to the ignition (switched live) at one end, and alternator at the other, so I don't think a stray 'live' would be that.....

In case it helps, the things I can think of for a permanent live are -

Radio/CD
Hazard flasher switch
Courtesy Lights
Main key switch
Light switch

[v8s4me]

On checking again this morning it seems the volt meter isn't working either now and I've found another stray live.
Should this terminal on the back of the volt meter be connected (bottom left in photo)? To a live feed?

[jeff m2]

Without looking at the diagram.

The charging light (of any car) is battery backed.
The other wire of this light goes to the field coil of the alternator.
So.....with the alt at rest there will be a ground condition. Current will flow and the light will glow.
Once the alternator is charging there will be 12v at the field coil....and as it is connected to a light also has an equal voltage there will be no current flow and light will not glow.

However it should not be live all the time. (only with the ignition.) Are you sure it all the time?

Get diagram, check battery run.

[v8s4me]

jeff m2 said:

....Get diagram, check battery run.

Anyone got one?

[adam quantrill]

Joe - what exactly have you got - model and year - before we point you at wiring diagrams, as there are different ones, depending.

[v8s4me]

1981 280i Tasmin FHC S1



Fuse board looks like this...



This is the fuse layout...



Does this help?

I have a mate with an early Tasmin and the wiring diagram he has indicates the live feed to the volt meter comes off the left side of fuse 12.

[v8s4me]

jeff m2 said:

....The other wire of this light goes to the field coil of the alternator.....

There are three wires coming off the back of the alternator. Two heavy brown ones and a light gauge black one. According to diagrams I have looked at, this black one should go to the volt meter. Mine goes into the part of the loom leading into the headlights. This doesn't look right, but it does look original.

I'm still trying to trace the wire from the back of the charge light bulb.

[mrzigazaga]

v8s4me said:

I'm still trying to trace the wire from the back of the charge light bulb.

Hi Joe

I would of thought that that would come from the alternator?

[v8s4me]

mrzigazaga said:

... I would of thought that that would come from the alternator?

Hi Mrk. Mine goes into the part of the loom leading into the headlights. Anyway, I have now got both the charge light and the alternator working! I'm not quite sure how, but I'm happy they are now working.

The next knock-on problem. Once everything started working properly again the RH headlight pod has thrown a wobbly. When I switch the headlights on, both pods pop up as required. When I switch off, both lights go off and both pods go down but the RH pod pops up again (no light) and then goes down. Weird!

Any suggestions anyone?

[mrzigazaga]

v8s4me said:

The RH headlight pod has thrown a wobbly. When I switch the headlights on, both pods pop up as required. When I switch off, both lights go off and both pods go down but the RH pod pops up again (no light) and then goes down. Weird!

Mmmm...It could be that the armature is slightly out of sync with the other..Before any adjusting bring the pods up...Then disconnect the battery...Check by manually winding the offending pod with the dial on the bottom of the motor from underneath that it is at its fullest stop position when up.

If not then wind to this point...Its where it starts to drop again....Then re-connect the battery and close the pods..If it still does it then pods up to highest point again..Battery off..Remove the lamp units from both pods and inspect the armatures on both to see if they are equal..There is adjustment on the arms but I would only do this if its really needed....


Ziga

[jeff m2]

v8s4me said:

jeff m2 said:

....The other wire of this light goes to the field coil of the alternator.....

There are three wires coming off the back of the alternator. Two heavy brown ones and a light gauge black one. According to diagrams I have looked at, this black one should go to the volt meter. Mine goes into the part of the loom leading into the headlights. This doesn't look right, but it does look original.

I'm still trying to trace the wire from the back of the charge light bulb.

Brown is the colour of wires considered "battery", the third wire, probably a thinner gauge will ultimately go to the charge light, if there was an intermediate connection to the voltmeter, that would be ok. (the voltmeter needs to know the value of the output, the charging light just needs a "yes or no").

PS the dancing headlight pods are a symptom of lack of use, ignore it for now get the wiring done first.
One job at a time.
Operating pods five or six times may be enough to clean the contacts.

[v8s4me]

Thanks for all the help and suggestions. I think I've finally go to the bottom of this. After getting everything working at around 5pm I started tidying everything up, zip-tying, covering cables with split conduit etc only to find the charge light and volt meter weren't working. By accident I'd left the AVO connected to the HRS circuit and noticed that it was only showing around 10V. There was no charge! So, everything back off again and started pulling and twisting wires. Eventually the answer. What seemed like a good connection this morning wasn't. Once I'd separated the lighter gauge black wire from the two heavy brown ones the faulty connection became obvious...



There were probably just a few strands of wire making contact and these finally came away once I started the tidy up. Too late to fix it today but at least I know where to start next time. Hopefully that will be it. Not a totally wasted day because a lot of very dodgy wiring got fixed hopefully preventing further problems down the line.

And the "dodgy wire"? That turned out to be the permanent live feed to the clock.

I've also sorted out what the relays control and I'll post that up later.

Thanks again for all the help.

[v8s4me]

Relay Layout.......