Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Speedometer Calibration

That looks like the correct plug for a later M3W. If you short the two pins, turn on the ignition and it puts the speedo display shows "Pulse" then you are into the calibration set up.

Great, thanks for your help as always👍🏼

There’s 12v on one of the pins with ignition off, is that right or have I got the wrong connector block?

Looking at your photo again (and reading through my own instructions) that isn't the correct plug, sorry. It should have a Black wire with a Grey and Black wire. The plug is a white plastic one on early cars and a black one on post 2014 cars. As I didn't know, I have had a check of what voltage should be on each pin and it is nil on both with the ignition off and 5v on the grey and black pin with ignition on, the black is an earth. Hope that sorts it, back to trying to find the correct plug now. If your car has heated seats the plug may be above the gearbox, visible from below? If no heated seats it is usually near the fuse box...... but it can be anywhere depending on the mood of the person who built your car that day.

It does have heated seats so as you say back to looking.
Thanks for taking the trouble, TM is lucky to have your expertise.

I still haven’t found the configuration wire, even removing the gearbox cover to have a look, I know it’s some where but I can’t find it!

As the inaccurate speedo bugs me I did a workaround which may help others in the same predicament.

Remove bulkhead for access and remove 14 pin connector from speedo by pressing tab.


Find pin 11 black and grey wire


Strip small piece of insulation from grey and black wire and attach fly lead with insulated bullet connector that is accessible in fuse box area.
I just twisted the wire together and wrapped with insulation tape rather than soldering or use a wire tap as suggested by Lightspeed.
Refit 14 pin connector block.

When calibrating just connect longer lead to bullet connector and sat in the car you can just touch wire on exhaust to earth it as per Planenut instructions to calibrate speedo. I.e. short and long touch.

Nice work around Obie👍 I too searched for the mysterious wire to no avail.

Removing that bulkhead is easier than pulling the transmission tunnel imho.

Thanks for the good clear Post.

No problem.
Just to confirm I didn’t cut the grey and black wire just joined onto it.

You could have used a crimp on TAP couldn't you? Or did you not want to leave the splice in place?

Possibly the plug with the Black wire along with a Grey and Black wire has been deleted on newer cars, as both your cars are more recent models. That is a good work around Obie, it achieves the same result. The set of instructions that was available to all and free to view on the MTWC website is now only available to members, following a tidy up of the web page.If anyone need the instructions I can forward them to you if you PM me.