The elusive early TR dash light rheostat

I’m willing to bet it’s a common fiat part.

 

The part number is 131467. According to Eurospares it's available:
https://www.eurospares.co.uk/parts/ferrari/testarossa-1985/interiors/instruments-and-passenger-compartment-accessories-for-us-version-my-1987-31074

 

I am no expert, but I have a feeling it is a linear taper potentiometer, and those would be available from any electronics supply house. If it were mine, I would pull the unit, read the numbers off the casing and call somewhere like Mouser Electronics. There are likely only a few wires connected and they wouldn't be hard to transfer over. Thinking outside the box. The joy of this car is that these are usually common parts underneath the expensive F car parts.

Hope that helps. The other thing you may want to try is a good contact cleaner. I use Deoxit, but there are lots on the market. You may be able to revive your notchy/semi working one, if that is the case.

 

I was able to clean the oxidation from mine with a pencil eraser.

 

Is the AC/Heat switch the same way?

 

I don't know, I keep mine on MAX cool.

 

Just used the eraser to gently remove the oxidation from the copper, I believe I had to disassemble it.

 

Will just add the comment that rotating it once in a while (to wipe the brush over the windings) will help keep it healthy (vs leaving it in one place for 3 decades ).

 

Stupid comment to add, but I rarely drive at night and the last time, went to use the rheostat and turned it to the right - no response, after several tries.

Turned it to the left and the dash lights came on perfect. So, ignorance on my part at its best or Italian engineering at its best.

Take your pick.