Lucas 953066. It appears to be a resistor, it's in the loom in-line with spade connectors. After weeks of poor starting and the engine cutting out I have finally discovered this damaged, rusty part is the culprit! So is it necessary? Where do I get a new one? What does it do?

No it's actually in the loom under all the plastic wrap,

I've found a pic online here

http://photobucket.com/images/LUCAS+RD+953066+Resi...

I had an issue with the Rover Sd1 Vitesse I had.

This item was found to be the culprit after much grief, and buried within the loom and not featuring on the factory circuit diagrams either.

It would go open circuit once at a certain temperature and cut the 12v supply to the ECU. It took ages to locate the fault - and we had ever helpful Lucas electronics on the same Acton industrial estate too.

If you can get the rating any old resistor will really suffice, suitably wrapped/insulated in self-amalgamating tape or similar - but in a location you can get at if it still is problematic. Something jangles in my head that it was a 57k but it was circa 23 years ago

Okay, just a quick update. Managed to locate a new resistor at Racing Green, they only had two in stock, looks like these parts may become hard to find. Cost was £9.50. For reference the Lucus Part Number is FDB943.

I've now re-routed the wiring so the ignition resistor is in the rely/fuse bunch and is accessible, rather than hidden under the loom shrouding.

Have a look at my pics above, it's in the footwell loom, under the plastic shrouding, where you see the two spade terminals, mine got damp and rusted through, you can see the remains in the second pic, it's still plugged into the spade.