Oil temp problem

The car is a 512TR: when at idle the gauge functions normally. As soon as the engine revs past say 1200, the reading drops to the left peg, or effectively no reading. I have checked the sender unit which shows a 100 ohm resistance at ambient, same as a new one.

I think I have a ground problem - does anyone know how to find the part# on the wiring diagram?

Any suggestions?

 

Very good question !! There is no sign that the wires are damaged at all as the rubber protective sleeve extends about 15 cms above the plug. When I peeled back the rubber seal over the plug, the crimped connectors looked good too. But a ferrari dealer tech has warned me that these wires can break internally because of their heat exposure. This may also explain why the gauge works when the alternator output may be lower at idle permitting the current to flow at the higher resistance of an internally broken wire. So I have to do some continuity testing tonight.

Another suggestion he has made is much more demanding to find which is a breakeage in connectors between one of the 4 circuit boards that constitues the fuse and relay panel. testing those will be beyond my skill and confidence.

Thanks for your response though - you might be on the numbers.