What Does this Dial do?

[garageguy]

Hi Everyone,

Restoring my dash and I have this horizontal dial above the warning lights...I don't see this on other '74's like mine and I can't seem to find the schematic in the wiring diagram. Nor does it seem to do anything when I move it.

Here's a link to a pic I found online...can you help me identify it please: https://s.aolcdn.com/hss/storage/midas/ ... Martin.jpg

[Nanonevol]

It's a dimmer for the dash lighting. Many of us delete it as the dash stock dash lights are quite dim as it is.

[garageguy]

Thanks. So are there two dimmer switches on dash? The one with the black knob on the right thought controls my dash lights?

[garageguy]

Sorry for another post. So the horizontal dial originally in question seems to change the green light intensity on the Hazard button. The knob dial does change the dash lights. Not sure why the horizontal dial is necessary

[DieselSpider]

The previous owner may have done some customization's. The upper horizontal wheel is the dimmer control for the ideograms lit by the single bulb for the fiber optics such as on the heater controls, the bottom left knob is the wiper speed control and the bottom right knob is the instrument cluster dimmer.

[GeorgeT]

The knob in the first photo is to change the speed of the windshield wipers from slow to slower.

[18Fiatsandcounting]

DieselSpider and GeorgeT have it right.

[Rant On]
And, just a personal rant of mine, but I never understand why controls that are safety related are written in plain English so that all can understand ("Brake Failure", "Hazard", "Fasten Seat Belts", etc.), but when it comes to other controls and warning lights, we are provided only confusing and hard to interpret hieroglyphics, and left to scratch our heads or ask others...
[/Rant Off]

-Bryan

[garageguy]

Thanks guys...then why do so many pics of these car dashes NOT show this dial? Was it a custom add on or did people just delete it?

[18Fiatsandcounting]

I'm guessing it's a customized add-on, but I'm open to being proved wrong. In all the spiders I've had over the years, I've never had one that had a "thumbwheel" such as yours. The only dimmer switch was the black knob on the right, and that controlled the dial lights, the orange ring around the cigarette lighter, and the illumination on the heater/vent controls. With the caveat that I haven't run across all model years, especially later years.

-Bryan

[garageguy]

The plastic on the dial (internal) has a '73 date stamped on it. So it's an original part for sure. Just don't see it wired in any schematic I've seen.

[aj81spider]

I think it was only around for a few years (including and maybe only '74).

I have a '74 schematic with it depicted. PM with your email if you'd like a copy.

[DieselSpider]

I'm guessing it's a customized add-on, but I'm open to being proved wrong. In all the spiders I've had over the years, I've never had one that had a "thumbwheel" such as yours. The only dimmer switch was the black knob on the right, and that controlled the dial lights, the orange ring around the cigarette lighter, and the illumination on the heater/vent controls. With the caveat that I haven't run across all model years, especially later years.

-Bryan

The info I posted was quoted from the Factory Printed owners manual published by Fiat that came in the glove box of my 1978.

[18Fiatsandcounting]

The info I posted was quoted from the Factory Printed owners manual published by Fiat that came in the glove box of my 1978.

Good to know DieselSpider; thanks for keeping me honest. I did own a '78 spider for many years (bought new by my parents and later transferred to me), but it did not come with the thumbwheel. Just the black knob on the right. Perhaps the former was an option?

-Bryan

[DieselSpider]

The info I posted was quoted from the Factory Printed owners manual published by Fiat that came in the glove box of my 1978.

Good to know DieselSpider; thanks for keeping me honest. I did own a '78 spider for many years (bought new by my parents and later transferred to me), but it did not come with the thumbwheel. Just the black knob on the right. Perhaps the former was an option?

-Bryan

Not sure as in 1978 I was more into Big Block Muscle Cars and 4X4 Pickup Trucks so at that time gave cars like the Spider little notice.

From what I've read around that with the Spider being a somewhat handmade vehicle where the parts were only loosely to spec the assemblers had some latitude in selecting parts that fit and so it is possible that at times when they ran short or found that it was too tight a fit to use the panel with the thumb wheel that they used an older panel without the thumb wheel to move the car along and get it finished. Lets face it the backlit ideograms even at full intensity aren't very bright and even if they were they are all below eye level under your right arm.

[garageguy]

Thanks all for the detailed comments. The oddity of this dial's fxn and on limited cars, it certainly adds to the charm.