Speedo/tach/etc lighting rheostat (1977)

[msrichmond]

I have four of these, none that work. I sacrificed the ugliest one to see how it comes apart. I sliced the plastic knob off, bent back the tabs on the back of the case and it slid right apart. It looks like this assembly could be cleaned and made to work.

But I can't figure out how the knob would come off without destroying it. There is a pin that goes into the shaft holding the knob in place but it is inserted through a hole in the knob and does not appear to be something you could disassemble.

Any ideas?

MikeR

[azruss]

they are not liquid tight. you may want to see if you can spray some contact cleaner inside and and work the knob like crazy. you can test it using an ohm meter.

[spider2081]

The Rheostat used on my 1981 Spider has an internal fuse. Any short in any lighted instrument will blow that fuse and the dimmer will no longer work! The terminals on the back of the rheostat are labeled A,B,C,and D. A and E are power in and out. The other 3 are cut off and no external connection. The internal fuse is attached between terminals B and C it is a very thin wire. I have fixed mine by soldering a single strand of wire from a #16 gauge wire between the terminals. # 16 gauge stranded wire I have is made of 19 strands of #29 wire. So I think its like a 1 amp fuse.

[msrichmond]

https://fiatspider.com/f08/viewtopic.ph ... 33#p225633