Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Turn Signal Module - Lets build a better one!

One of these maybe...

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Also used on Austin A35's

My first car was an A35 (Noddy Car) with flip out indicators and a switch just like that, great car used to drive from North of England to Devon in it before Motorways existed.

Holden sell them, they also come in Black.

Problem is that it has no inverter. It also fails...a lot.
It does more than control the indicators, it works alongside the ECU and if it fails, you are unlikely to turn the engine off, even if you take the key out.
Over running is ok as you can stall the car,starting it again is another matter. The part is cheaply made £50 or so which means production is likely to be £5-10 max.

The opposite of over engineering is required so that it does fewer tasks in a more reliable fashion.

Why not wire the toggle to an independent circuit and leave the evu out of it?

Hi Everyone

My friend Alister who is an Electronics Engineer has now tested my working spare Turn Signal Module & he wanted to share his findings:

He is going to suggest a retro fit solution in due course as Voltage spikes sure seem to be the problem here.


From Alister:-


The fault seems to be caused by a failure of the integrated circuit CD4072.

I have not fully copied out the circuit diagram but am 75% there and this fault showed up.

Its input pins go to the loom directly so any voltage spikes will destroy the 4072. Internal diodes inside then conduct power from the hazards circuit to the main ignition 12V feed hence a motor will carry on running with the ignition key removed.

As per usual, you are welcome to let the others know.

Regards,
Alister

Another update from Alister...


can easily design a replacement circuit board to go inside the existing housing. Conversely if the housing can be obtained easily then I think a slot has to be cut out, but that's all achievable. I don't know where the housing comes from or if the mounting holes are necessary/used/correct. If someone could supply that info then that would be handy.

TalkMorgan comments request a simple device that is more reliable, so I would propose removing the current sensing circuitry, the CD4072 and also connecting the repeaters directly to the indicators. For some bizarre reason, they are independent circuits!

Thank you and Alister for perusing this, particularly as it looks like you are sadly going to leave the band of owners. We will need more people like you in the future as these are the sort of this that will dog M3W ownership in the future.

I can only help a little with the information you are after. There isn't much (any) spare loom for the TSM and it's location is awful, I think they must start with a TSM and build the car around it. It has four attachment screws, you could get away with two but none of them are very accessible. I would like to say that a similar sized box with the same plug would be good enough but the location is very tight, so it needs to be no larger. I have attached a photo and that doesn't have the usual S&S ECU fitted, as it has a G56 Emerald ECU, with it's non standard loom in the photo. I hope this helps. Contact me if you require any other information please. Very happy to do all I can with this to help.