Ignition Warning Light as Oil Pressure Light?

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Dan1950

Dan1950

1974 MK II Roadster
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Looking at the MK II wiring diagram it appears that the ground for the ignition warning light is independent from any ignition circuits. I want to wire the ground to my oil pressure sensor so that it can be a combination ignition on indicator and a low oil pressure warning light.

Once the engine is running having an indicator light to tell me the ignition on is a moot point.

I have traced the wire and grounded it at the bullet connector under the tank to establish that the white/brown trace wire is the ground. Any idea where this wire terminates? It would be nice to just hook it up directly to the sensor switch to eliminate any splicing.
 
Dan1950 said:
I have traced the wire and grounded it at the bullet connector under the tank to establish that the white/brown trace wire is the ground. Any idea where this wire terminates?
Click to expand...

Red is 'ground' not white/brown.
White/brown (WN on the wiring diagram) is the wire between the charge warning lamp and the assimilator.
 
L.A.B. said:
Red is 'ground' not white/brown.
White/brown (WN on the wiring diagram) is the wire between the charge warning lamp and the assimilator.
Click to expand...
The ignition indicator is white (hot) white/brown trace ground/assimilator. It is that way on the bike as well as the wiring diagram. Can I just wire it to the sender switch? After disconnecting it from the assimilator of course.

The assimilator is the path to ground for the indicator light.
 
Dan1950 said:
The ignition indicator is white (hot) white/brown trace ground. It is that way on the bike as well as the wiring diagram.
Click to expand...

White is the warning lamp feed (-).

White/brown as mentioned should be the wire connection between the warning lamp and the assimilator (WL terminal) and red (connected to the assimilator 'E' terminal) is earth/'ground.
 
L.A.B. said:
White is the warning lamp feed (-).

White/brown as mentioned should be the wire connection between the warning lamp and the assimilator (WL terminal) and red (connected to the assimilator 'E' terminal) is earth/'ground.
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Does the light have to route ground through the assimilator for some reason? Once the engine is running the ground will be interrupted.

It will no longer be a dedicated ignition on indicator, it will be a simple oil pressure light which will double as an ignition on on indicator when the ignition switch is on and the engine isn't running thus no oil pressure.

I think you are over thinking this.
 
Dan1950 said:
Does the light have to route ground through the assimilator for some reason? Once the engine is running the ground will be interrupted.
Click to expand...

It's the assimilator that switches off the warning light therefore why WN connects to the assimilator.
Ignition Warning Light as Oil Pressure Light?

Ignition Warning Light as Oil Pressure Light?
 
L.A.B. said:
It's the assimilator that switches off the warning light and why WN connects to the assimilator.

Ignition Warning Light as Oil Pressure Light?
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And now the oil pressure sender will switch off the light thus no need for the assimilator. It will now be an oil pressure light, nothing more nothing less.

Where is the assimilator located on a MK II?
 
Dan1950 said:
It will no longer be a dedicated ignition on indicator, it will be a simple oil pressure light which will double as an ignition on on indicator when the ignition switch is on and the engine isn't running thus no oil pressure.

I think you are over thinking this.
Click to expand...

I'm saying how the warning lamp would normally be wired as it isn't just an 'ignition on' warning lamp but a charge warning light. If you want to use it as an oil pressure warning instead then you need to connect WN from the warning light to the oil pressure switch.
 
L.A.B. said:
It would be a silver can suspended by a spring under the fuel tank near the carbs.
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OK I think I figured out what the assimilator's purpose is. It seems that it may wired to the alternator as a charging indicator. If that's the case I would have to install and wire a dedicated oi pressure light or lose the charging indicator..
 
L.A.B. said:
I'm saying how the warning lamp would normally be wired as it isn't just an 'ignition on' warning lamp but a charge warning light. If you want to use it as an oil pressure warning instead then you need to connect WN from the warning light to the oil pressure switch.
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I figured that out just before you replied. Thank you for your patience.
 
Dan1950 said:
OK I think I figured out what the assimilator's purpose is. It seems that it may wired to the alternator as a charging indicator. If that's the case I would have to install and wire a dedicated oi pressure light or lose the charging indicator..
Click to expand...

You can get a combined charge and oil pressure warning light kit.
 
L.A.B. said:
You can get a combined charge and oil pressure warning light kit.
Click to expand...

I looked at that. Too complicated, too many bells and whistles and possible replacement issues down the line. I want to utilize readily available components.
 
L.A.B. said:
Ok, personally, I'd fit an oil pressure gauge.
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Already have one but can't see it at night. I could just tuck a flashing red LED near the front of the tank tunnel for nighttime riding.

Simple, easy and effective.
 
Dan1950 said:
I looked at that. Too complicated, too many bells and whistles and possible replacement issues down the line. I want to utilize readily available components.
Click to expand...
Dan,
That ICM unit is not that difficult at all to install.The beauty of it is that you get 2 indicators in one light. I have had one on my 74 for over 2 years with no problems whatsoever. I used Madass’s sending unit for the oil pressure.Everything fits nice and light is very bright.
Mike
 
Same setup and experience as Ying. Got the version with the very bright LED which fitted in my standard 850 Mk 2warning light holder.
 
YING said:
That ICM unit is not that difficult at all to install.The beauty of it is that you get 2 indicators in one light. I have had one on my 74 for over 2 years with no problems whatsoever. I used Madass’s sending unit for the oil pressure.Everything fits nice and light is very bright.
Mike
Click to expand...
Ibex said:
Same setup and experience as Ying. Got the version with the very bright LED which fitted in my standard 850 Mk 2warning light holder.
Click to expand...
Sorry, too "busy" for my tastes. Too many differing flash sequences. I'm going to investigate adding another indicator light of some sort.
 
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Dan1950 said:
OK I think I figured out what the assimilator's purpose is. It seems that it may wired to the alternator as a charging indicator. If that's the case I would have to install and wire a dedicated oi pressure light or lose the charging indicator..
Click to expand...
You could actually use the same bulb for both. Since the light is on when the assimilator applies ground and your oil pressure switch also applies ground, you could wire them in parallel. The lamp then becomes a "fault" indicator, but you won't know if it's an alternator or oil pressure fault. Another option would be to repurpose the high beam indicator lamp.
 
maylar said:
You could actually use the same bulb for both. Since the light is on when the assimilator applies ground and your oil pressure switch also applies ground, you could wire them in parallel. The lamp then becomes a "fault" indicator, but you won't know if it's an alternator or oil pressure fault. Another option would be to repurpose the high beam indicator lamp.
Click to expand...
Yes I have considered that. I do have the Old Brits oil pressure gauge to reference if the "fault" light comes on. I just want an oil pressure light for night time riding. There is also a space for an additional indicator light between the high beam indicator and the light switch.
 
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