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Redundant wire from oil filter - green

Posted: Sun Aug 25, 2019 6:46 pm
by Jaywhy
I have converted to a spin on oil filter and I want to use both the single redundant green wire from the old oil filter and make use of the yellow warning light that it feeds. Can anyone tell me whether the green wire is a “live” feed OR an “earth” feed to the warning light?

Also If I put this wire to earth will the yellow warning light illuminate?

Re: Redundant wire from oil filter - green

Posted: Sun Aug 25, 2019 8:47 pm
by StillGotMy1stCar
If I have understood you correctly, you had a blocked filter warning light fitted that is now redundant.
If so the green/yellow wire you mention earths the light to illuminate it.
At the moment the 12V supply goes to the bulb and it earths via the switch.
If you want to illuminate the light with a 12V supply on the green/yellow wire then you will have to remove and insulate/isolate the supply to the bulb behind the speedo and earth the bulb instead.
If your car never had the filter switch fitted then it is unlikely to have the bulb and holder fitted but you could add one if needed.
Hope that makes sense.
Regards John

Re: Redundant wire from oil filter - green

Posted: Tue Aug 27, 2019 4:16 pm
by Jaywhy
Hi John - thanks for your reply

The redundant wire that I took off the oil filter when I replaced with spin on type is definitely all green and on further investigation goes directly to the back of the alternator. I assumed incorrectly that it directly ran from the filter up to the yellow warning light in speedo.

Can you throw anymore light on this for me?

Thanks - Jeff

Re: Redundant wire from oil filter - green

Posted: Tue Aug 27, 2019 4:59 pm
by StillGotMy1stCar
Was this green wire on a pressure switch?
Sounds like a silly question but I wondered if it was an earth for the alternator, although I've not come across an alternator requiring a separate earth.
Also are you sure it doesn't make it's way to the Charge warning light.
Does the charge light go out if you pull this wire off the alternator.
Regards John.

Re: Redundant wire from oil filter - green

Posted: Tue Aug 27, 2019 5:48 pm
by geoberni
I guess it depends on the alternator that was fitted; I'm assuming its not the Morris original fit.
According to the original manual Plate N46, the Morris fit was a 3 wire system, because it had an external Control Unit, but colours were Brown/Yellow, Brown/Green, and Brown/White.

Pretty much all retrofit upgrades are only 2 wire because the Control Unit is built in.

Perhaps this is an early attempt at an upgrade? :-?

Jaywhy - has it got a separate control Unit?
Not that it would explain why it went anywhere near the Oil Filter. :-? :-?

Re: Redundant wire from oil filter - green

Posted: Tue Aug 27, 2019 6:06 pm
by StillGotMy1stCar
What I was finally going to say was it is possible to have the blocked filter switch in parallel with the warning light connection on the alternator. I had a car in the 80’s with just one warning light marked Oil but was also the Charging light.
Ideally Charge is Red, Oil is Orange which I have assumed you are calling Yellow.
Perhaps a photo of connections at rear of alternator would help.
Regards John

Re: Redundant wire from oil filter - green

Posted: Wed Aug 28, 2019 8:27 am
by IslipMinor
Definitely need to see where the green wire is connected to on the alternator. I cannot see how any connection from the alternator would be connected directly to either the standard oil pressure switch, or the filter by-pass switch. They are both 'green/yellow' and both switch a bulb to earth - switching an alternator connection to earth is not a good idea!

Plain green wires are the ignition switched feeds from fuses; there should not be any connection directly from green to earth.

Re: Redundant wire from oil filter - green

Posted: Wed Aug 28, 2019 9:43 am
by StillGotMy1stCar
Thanks Richard; Just to clarify the car I had with single warning light factory fitted was a Mazda I later added a separate warning light to the alternator.
Earthing the warning light connection terminal on the alternator may cause damage to the alternators regulator.
I’m not recommending anybody tries combining oil and charge light but on the OP’s car someone may have mistakenly done so.
Regards John

Re: Redundant wire from oil filter - green

Posted: Thu Aug 29, 2019 9:45 am
by Jaywhy
Picture showing green wire attached to back of alternator
Picture showing green wire attached to back of alternator
0D3DFFBE-7883-4318-9FF8-AD7C9711E333.jpeg (1.5 MiB) Viewed 2606 times
.jpeg[/attachment

Please see two photos of green wire that I removed to install spin on oil filter

Re: Redundant wire from oil filter - green

Posted: Thu Aug 29, 2019 10:11 am
by StillGotMy1stCar
I can’t tell from the close up image what make of alternator that is, if it’s a Lucas type then that terminal is a high current output that will have destroyed the oil pressure (blown it open circuit).
A photo showing the whole alternator would be appreciated.
A Lucas type has two large and one small terminal, which are two outputs and the small warning light.
Best find out what alternator first as you can use that large terminal to double it up with the other feed to the solenoid.
Regards John

Re: Redundant wire from oil filter - green

Posted: Thu Aug 29, 2019 10:39 am
by IslipMinor
The picture of the terminals looks like a classic Lucas alternator connector setup. If it is, then connecting a wire from the centre 35A Lucar terminal to the oil filter switch is pure madness! The terminal one of two on the alternator that are connected directly to the battery (no fuse), via the starter switch/solenoid, and if the filter switch had ever closed, the green wire could have melted and very likely set fire to the car. Do you know fitted it, and why?

An 'all bright green' wire is not a colour ever used on a Minor, and I would remove it immediately from the alternator, before there is any risk of it shorting out.

Re: Redundant wire from oil filter - green

Posted: Thu Aug 29, 2019 11:57 am
by geoberni
I totally agree with the last 2 posts, having a wire from the alternator output terminals going anywhere other than the battery, and therefore the car's 'systems' is complete madness.
Either someone has got very confused fitting the alternator modification, or at a latter date, someone has had that wire fall off and reconnected it to the first thing they found, i.e. the oil filter terminal.
Whatever the cause, you've been very lucking not to do some serious damage. Remove it.

Re: Redundant wire from oil filter - green

Posted: Thu Aug 29, 2019 3:43 pm
by Jaywhy
[attachment=0]6F7609B4-3353-4BE4-BF19-8EE8922A40F8.jpeg[/attachment
Thanks all for your input - I am pleased you told me the need to remove this wire - which I have now done - although I am now looking for an alternative as I wanted to use this redundant wire to feed a float level switch I have installed in my break fluid reservoir that is being used for my disc brake/ servo setup I have fitted - the idea being that if my brake fluid was lost then the yellow spare light that was being used initially for filter blockage would illuminate and warn me of low level.

Re: Redundant wire from oil filter - green

Posted: Thu Aug 29, 2019 11:16 pm
by StillGotMy1stCar
It might be worth looking for the Green/Yellow wire, one will be on the oil pressure switch on the block and the other will be nearby. It sometimes mistakenly gets connected to the ignition coil or is just left hanging/taped up in that area. If you do find it earth it and see if the warning light works. As I said earlier it may not have a bulb holder fitted but the Green/Yellow wire should still be present in the engine bay.
If you need a bulb holder I have spotted this:-
https://www.ebay.co.uk/itm/Morris-Minor ... SwVoFar-Qh
Regards John.