How to replace dimmer switch rheostat in and 80-82 Spider?

[Betis]

What do I need to do to replace the switch in the dash?
Thanks in advance

[GeorgeT]

If I remember correctly, you remove the upper and lower column covers, the steering wheel and the horn components. The on/off/high/low switch is then accessible. I probably forgot something but it is pretty straight forward and doesn't require any special tools

[spider2081]

Here is what I do.
First tie a long string to the knobs of both the dimmer control and the wiper speed control. The string needs to be strong but not too thick. Secure the other ends of the string to the shift lever so you don't lose them. Unscrew the chrome nuts securing the wiper speed switch and dimmer control and slide them down the string away from the panel. The rectangle area with the warning lights will now pull away from the dash. Slide it down the strings out of the way. The dimmer (with string attached) can now be pushed back and pulled out the hole in the dash where the warning lights fit. Transfer the wires from the old dimmer to the new dimmer. Transfer the string to the new dimmer. Use the string to pull the new dimmer through the mounting hole in the dash. Slide the rectangle plastic piece with warning lights back in place. Holding tension on the string slide the chrome nut back in place and tighten. Do the same with the wiper speed control.

Hope this makes sense.
The dimmer controls have an internal fuse. If there is a short in the dash light circuit this fuse will blow. You might jump the dimmer wires quickly to see the dash light work before installing the new dimmer. If there is a short you would blow the fuse in the new dimmer when you hook it up and try it.

[TX82FIAT]

I know we like to restore things to original spec. However, the dimmer light is one of those exceptions. It really hardly works in the first place. You can keep the dimmer switch in the dash for looks. However, I recommend a jumper wire to eliminate a know week spot.

[divace73]

I know we like to restore things to original spec. However, the dimmer light is one of those exceptions. It really hardly works in the first place. You can keep the dimmer switch in the dash for looks. However, I recommend a jumper wire to eliminate a know week spot.

that is what I have done

[toplessexpat]

..... and this also depends if you have a car made during the wonderful mid 70s period when it was a design feature to have TWO dimmers. One (the knob) for most of the dash lights, and one (the wheel) for the center console and ideograms.

I've actually kept the knob one and used multi element LEDs in the dash. They fade pretty well, for when the dash is just too bright!!! (I know - not a common complaint on these cars)

[Betis]

Replaced, thank you all of you

[Weezerwill]

This procedure is very detailed. However, when I tried on my 82 the rheostat would not fit through the diamond cutout in dash. Dash was replaced at some point. Anyone run into this before? Any other way to get the rheostat. out?

[Weezerwill]

Today I tried attaching two different rheostats with no luck getting the dash lights on. Even if it worked I still could not get it in the dash due to my issue with the cutout. Anyone know a good Fiat mechanic near Boston, MA?

[spider2081]

Today I tried attaching two different rheostats with no luck getting the dash lights on

The parking lights have to be on for the dash light to function. Is the green "lights on indicator" in the speedometer lighting with the key "on" and the headlight switch in the center position?
If so the dash panel light toggle witch and the fuse 8 portion of the circuit are good and you should have power to the dash dimmer control. Have you tested for power on the yellow/black wire at the dimmer control?
I use an 3 amp inline fuse to connect the yellow /black wire to the white/red wire. This should make all the dash light lite full bright if the circuit is good and the dimmer is at fault. If the inline fuse blows there is a short in the dash lights circuit after the dimmer. A short usually causes the internal fuse in the dimmer controls to blow.

Hope this helps

[Weezerwill]

Yes, the green dash light comes on with parking lights. I made a jumper, but decided not to use it because it didn’t have a fuse. I figured I would try the new rheostat. I hope I didn’t just blow the interior fuse in a second rheostat. I’m now leaning towards a ground issue. I did replace the #8 fuse to be sure that wasn’t the problem.

If it is a ground issue, where would I start? Also, the dash has a bunch of light bulbs, if one is bad do they all go out like old Christmas tree lights?

I appreciate the help.

[redcars]

Your dash lights go out one at a time they do not depend on each other. You have a ground pod to the right of the steering column. Check it's connection to the car and check the connection of all the ground wires that go to it.

[Weezerwill]

Thanks, I’ll take a look

[THEFIAT]

I have most stuff off of the ignition switch onto relays using Csaba's relay set, which I lengthened to put the relays into the engine bay.

Does Csaba's relay set move the panel lights onto one of these three relays?

Guess, I'll look at bypassing the dimmer next.

Jon

[Mheinle]

This procedure is very detailed. However, when I tried on my 82 the rheostat would not fit through the diamond cutout in dash. Dash was replaced at some point. Anyone run into this before? Any other way to get the rheostat. out?

I know this is an old post and someone may have answered this, but to get the rheostat out push it of to the left toward the steering wheel as far as you can. Then reach up under the dash between the steering wheel and dash and grab it. Reinstall in the opposite manner. I know not a sophisticated way to swap it, but it eliminates having to go nuts taking the dash apart.