Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Speedo stopped working

Yesterday we stopped at lunchtime and the speedo was working. After lunch I backed out of the parking space and as we started off I noticed it had stopped working. It has power and the needle flicks when the ignition is turned on.

Any ideas?

Hi Peter, just looked at GoMog pages which has a one paragraph on the subject suggesting getting the speedo tested, or replaced or changing a little capacitor behind the speedo. Not overly helpful I am afraid.

I have a tacho issue that I am awaiting a response from Caerbont near Swansea
regarding a fix or a replacement instrument.

If at all possible best thing to try is swapping instrument to see if it is that or cabling or the instrument panel PCB (I'd guess a dry joint on the PCB)

If you are feeling adventurous drop the dash and remake the instrument connections and loom connections to PCB - do this with the power off maybe with the battery disconnected.

More than likely the bracket holding the transducer to the gearbox or faulty transducer

I will elaborate a little later but it seems it was a fuse. Just wanted to say it is working for now.

A result. Well done Peter.

Slightly off topic: the little trip set button stoped working.

I took it off, seems it is a simple "push close circuit" switch. Only it wasn't.

I unsoldered it from its wires, then squirted contact cleaner down into the body and turned the button round and round.

Dried out it sems to be working fine. But I need to plan a replacement....I suspect it has a limited life.

You been fiddling again Peter

OK so here is my eloboration.

As I said before it seemed that the speedo was getting current because the needle flicked when the ignition was turned on and the kilometers were showing on the display, but not updating. For this reason I did not suspect fuses.

This morning I went to the car to remove the dash to check for any loose wires but the only screwdriver I have with me is too big for the tiny screws that hold the plastic under-dash panel. I then noticed that some other dash functions and the fan were not working. Hmm! time to check the fuses. Naturally I checked about 10 before I found the culprit, a 2.5 amp fuse. Replaced the fuse, a miracle the speedo was now working. I turned on the fan, great that was working too. I changed the fan to high speed - phaff! Fuse blown. I replaced it again - same result.

So I can run the fan at low speed but until I pull the dash I can't use high speed. I suspect the problem may be that reported by another TMer; ie. that the back of the fan switch or the heater switch or somesuch has cut through the insulation on the fan wire, in this case the high speed circuit.

Anyway something to keep in mind: the fan, the warning lights, and the operation of the speedo are all on the same circuit. The lighting of the speedo, the display, and the start up flick of the needle when the ignition is turned on are on a different circuit.

My speedo stopped working today, just put my hand up the back and tightened the cable up ( worked loose) all sorted. Ahh simple Smiths instruments every time for me . The benefits of 80's cars ( there have to be some !)
But seriously
I Hope you get yours sorted