Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Dash PCB-ectomy

Wouldn't presume they're reset-on-power down ...The zero-volt switches on machine tools do, but other latching switches are mechanically latched and just toggle between on and off each time they're pressed ....so would stay in whatever state they were regardless of ignition status.

K

A latching switch does what it says…when the button is pressed to ON, it stays in that state until the button is pressed again to go OFF. However, the electrical supply may well be cut if it is sourced via the car ignition switch when that is turned OFF. But when you turn the ignition switch again to ON, items controlled via the push button either directly or via a relay coil, will come on again, until it is pressed once again to the OFF position. So having buttons or switches that light up when ON is very useful in reminding you that items are still switched on.
Good luck with your task but bear in mind that there is a fair amount of soldering and crimping activity involved in a tight space, together with searching for the correct wires hiding in the loom!

You wouldn't want a hazard switch to self cancel on engine off. Thankfully this is not the case with the mechanical latching switches being discussed. 2014 on Classics use momentary switches though with electronic logic latching. This usefully cancels selection of rear fog light, screen demist etc. on engine off, the exception being hazard switch of course.

I fear our woes began as earlier as 2003 with the introduction of ‘smart’ momentary latching and the ‘clever’ dash PCB using a micro controller.

What was ever wrong with a simple rocker or toggle…..

2003 Plus 8

What was ever wrong with a simple rocker or toggle….

Especially in a Morgan ... by their nature Morgan owners have made a deliberate choice for anachronism ... if you're happy with living with a Morgan in the first place then proper toggle switches are just part of the deal and unlikely to be a deal-breaker .... Whereas failing and irreplaceable quasi-modern electronics are definitely going to tick people off

K

Yes maybe a step too far too soon . Seems to be reliable on the BCU controlled models though as with every new car on the road now.

We saw yesterday the latest CX models now have auto lighting control with sensor just behind bonnet hinge. Whatever next

Having read this "wires hiding in the loom", the pics below might be useful.

Here’s which bundles are hiding the relevant wires.


And this is the original G55 wire (the one that has to be removed).
I didn’t totally remove my G55, I just pushed the contact/spade out of the connector and parked it in the spare slot behind its original position.
Luckily the spare slot connects to nothing and easy to convert back if needed.



A word of caution too for anybody following the wiring diagrams in the parts book...

These connector didn’t exist in my 2011 car.


It was actually more like this

Over the months this thread has become even more fascinating, some very clever people involved, especially Rog, keep up the good work chaps

Thanks Jon We must have just about flogged this one to death by now….

Again thanks all for this excellent information, thanks Richard for the clear explanation of mechanical and momentary latching differences and which system uses which!

Rog, an excellent visual on the wire locations!