MK3 Ignition Light Issue

R

raleypc

Joined
Mar 24, 2011
Messages
16
Country flag
Here is another MK3 Warning light issue. My MK3 had some generic replacement warning lights in the dash that were all working properly. The decal was shot and I wanted to get a more original look. I had the original lens and bought some neon bulbs from AN. I disassembled the dash, replaced the decal, and carefully (I think) reconnected and the correct wires to the new bulbs. Now my blue high beam light is dim, and of more concern, the red ignition light stays on after starting. I verified the battery was charging with a voltmeter and revving the throttle. Could I have somehow killed the warning light simulator? I did try and connect one the generic bulb assemblies in place of the new neon bulb and got the same result. Another issue is that my warning light wire colors do not match what is presented in the factory workshop manual. Any suggestions are welcome.
 
You are not by chance running a Podtronics or Trispark reg/rectifier as the std warning light assimilator will not work with either of these.
 
raleypc said:
Another issue is that my warning light wire colors do not match what is presented in the factory workshop manual.
Click to expand...

Yes, the console wires generally match the harness wires not the diagram.
 
Last edited:
raleypc said:
Running a MK3 Boyer
Click to expand...
But the question was are you running a modern reg/rec or the original rectifier with the two zener regulators? The moderns are usually note wired up to the assimilator so the lamp will not work as originally.
If your dash wiring is not oem colours, assume a previous owner has re-wired it and may have changed want components are in use. So got to investigate to see whats been done.
You are better off fitting a Battery voltage warning light like from https://www.improvingclassicmotorcycles.com/

These tell you more about what is happening, nattery is getting right voltage, not over charging etc. Original only tells you alt is pitting out some amount of AC.
 
Tornado said:
If your dash wiring is not oem colours, assume a previous owner has re-wired it and may have changed want components are in use. So got to investigate to see whats been done.
Click to expand...
That's just it, the console wiring colours don't match those on the Mk3 wiring diagram as I'd mentioned. Perhaps I didn't make it clear so I've edited my previous message to hopefully make it clearer.
 
According to the Mk3 wiring diagram the main beam warning lamp wires are two purples which is incorrect as the wires are actually blue/white and red.
The direction indicator has two yellows also incorrect as they are green/white and green/red.
Neutral is white and green not slate grey.
Ignition is white and white/brown not red so red is used but not as it's shown on the diagram.
So the console colours should actually match the harness wires shown in the plug. I don't know if the colours on the diagram were ever used.


MK3 Ignition Light Issue
 
Tornado said:
But the question was are you running a modern reg/rec or the original rectifier with the two zener regulators? The moderns are usually note wired up to the assimilator so the lamp will not work as originally.
If your dash wiring is not oem colours, assume a previous owner has re-wired it and may have changed want components are in use. So got to investigate to see whats been done.
You are better off fitting a Battery voltage warning light like from https://www.improvingclassicmotorcycles.com/

These tell you more about what is happening, nattery is getting right voltage, not over charging etc. Original only tells you alt is pitting out some amount of AC.
Click to expand...
Sorry about that...I am running the original rectifier with the two zener diodes. The warning lights were operating correctly until I changed the bulbs and lenses. I may have crossed some wires based on another poster's comments on the actual wire colors. I was not super careful when I pulled things apart as I knew I had a wiring diagram in the shop manual...not realizing that the colors were incorrect for the warning lights!
 
Genuin wiring found in my console. White wires for earth are missing.

Errata: White wires -Ve from the switch terminal pos. 2 . (Thanks, LAB)

20250927_163039.jpg
 
Last edited:
L.A.B. said:
According to the Mk3 wiring diagram the main beam warning lamp wires are two purples which is incorrect as the wires are actually blue/white and red.
The direction indicator has two yellows also incorrect as they are green/white and green/red.
Neutral is white and green not slate grey.
Ignition is white and white/brown not red so red is used but not as it's shown on the diagram.
So the console colours should actually match the harness wires shown in the plug. I don't know if the colours on the diagram were ever used.


MK3 Ignition Light Issue
Click to expand...
Thanks! If these is the case then I think I have some wires incorrectly attached. I will check this morning and report back.
 
raleypc said:
Sorry about that...I am running the original rectifier with the two zener diodes. The warning lights were operating correctly until I changed the bulbs and lenses. I may have crossed some wires based on another poster's comments on the actual wire colors. I was not super careful when I pulled things apart as I knew I had a wiring diagram in the shop manual...not realizing that the colors were incorrect for the warning lights!
Click to expand...
I just have to laugh when I read this becasue one WOULD expect the shop manual to be correct.
But here in the land of Norton's, nothing can be taken for granted. One has to confirm and verify EVERYTHING.
To think back in the 70's when I was in my twenties I thought I knew enough to work on these.
Thank Goodness for this website..

Thank You Jerry.....
 
MichaelB said:
I just have to laugh when I read this becasue one WOULD expect the shop manual to be correct.
But here in the land of Norton's, nothing can be taken for granted. One has to confirm and verify EVERYTHING.
To think back in the 70's when I was in my twenties I thought I knew enough to work on these.
Thank Goodness for this website..

Thank You Jerry.....
Click to expand...
One of the many, many reasons the bikes had reputations of crappy, failure prone electrics.
In reality, lack of familiarity & knowledge (🇺🇸) of them was a big cause.
I now know Joe Lucas got a bum rap (wrongly accused).
The Lucas was every bit as reliable as period Delco, Autolite.
 
Last edited:
possm said:
You are not by chance running a Podtronics or Trispark reg/rectifier as the std warning light assimilator will not work with either of these.
Click to expand...
I have a Podtronics reg/rec working perfectly well with the original warning light assimilator.
 

Similar threads

bucksfizz
  • Locked
Aftermarket Mk3 Ignition Switch
Replies
11
Views
2,159
bucksfizz
bucksfizz
B
  • Locked
Mk3 ignition
Replies
7
Views
1,713
JimNH
J
H
  • Locked
Ignition light issue?
Replies
4
Views
947
Headfullofsnakes
H
Reggie
  • Locked
MK3 ignition light bulb holders
Replies
4
Views
2,885
Reggie
Reggie
S
  • Locked
Brake light issue
Replies
13
Views
1,272
ChuckW
C
Back
Top