Hi, Just bought a 1982 Charleston.
Having a look under the bonnet, as you do, I noticed a black module nearside front.

It must be to do with the ignition because with the ignition turned on there is a green LED which is on: with the engine running, the green light remains and there is also a red LED which is lit and pulses.

Two wires go to the coil, one each side, the other down to the points area.

The previous owner did not do his own maintenance so does not know what it is.

Does anyone know which unit this is.

Thanks for any help.

see http://www.boyerbransden.com/IDunits.html

Thanks for your quick response. What's your opinion on this unit?

Does it do what it says on the box?

Look for a label or part number, take the lid off?

They are points assist ignition - I've fitted similar on all my A series over the years - reduces the current across the points so they last forever instead of burning out and increase the voltage of the spark - usually help with wet and cold starting and can give slightly better fuel economy - very handy for static ignition checks as the light either goes out or comes on depending on model when the points separate.....

Thanks for all the info, very useful.

One important question: knowing my luck, the module is bound to fail so if/when this happens, will the engine still run. Is there a fail-safe?

I've never fitted one of those particular makes - the old sparkrite ones used to have a switch that you could bypass in th event of failure but more often than not if you bypass them the car won't start as the capacitor has often been removed from the points box - you can rewire them quite easily to bypass but you will need to have a capacitor wired into the circuit in a convinient position on the engine.....