Thumb wheel dimmer switch question.

[Welder guy]

A friend of mine is having an issue with his thumb wheel dimmer switch ( 1969 era ) and I have a few old used ones he can use. The question I have is how can they be tested before hand to make sure there good to use. It would really suck to pull the gauge cluster and switch’s just to install a bad thumb wheel switch. We know there is a rebuild service in the states but after exchange, duties, shipping and taxes the switch would cost about $500 Canadian. The switches I have for him are free. Thanks in advance

 

[Fury440]

Here is a simplified view of a standard dimmer. The resistance wire is wound around a ceramic core, each end will usually end with a terminal. The silver wiper can bed rotated from one end of the coil to the other. They fail if the wiper contact with the resistance wire get dirty and/or corroded. A bad connection creates heat which will burn or melt the resistance wire.

To test, use an ohmmeter on each end of the resistance wire, the meter should read some value of resistance. Lets say it reads 100 ohms. Now put one meter lead on one end of the resistance wire and the other on the wiper connection. Rotate the switch from stop o stop, the reading should smoothly change between zero and what ever you read end to end, ie 100 ohms.

I have a NOS dimmer in the Fury that doesn't work right, probably why it lived on someone's parts shelf so long. A year or so ago @CanCritter gave me a mint looking spare he had and unfortunately it looks NOS but doesn't seem to have a connection between the wiper and the resistance coil. If you don't mind, hang on to your dead ones for me and I'll try to rob parts and rebuild one or both of mine.

 

[Welder guy]

My style of thumb roller switch looks different than the one in your picture. I have a few of these that I removed from my parts cars over the years . I have a whole drawer full of interesting switches for everything from a 1969 fury

 

[Knebel]

I had issues with mine too, pukpul it, degreased it, cleaned it all up and used plenty of "deoxit" on the coil. Lubed it a little and it works like abcharm again! I would take it out and have a look, it might just be very dirty

 

[Welder guy]

Here is a simplified view of a standard dimmer. The resistance wire is wound around a ceramic core, each end will usually end with a terminal. The silver wiper can bed rotated from one end of the coil to the other. They fail if the wiper contact with the resistance wire get dirty and/or corroded. A bad connection creates heat which will burn or melt the resistance wire.

View attachment 175226

To test, use an ohmmeter on each end of the resistance wire, the meter should read some value of resistance. Lets say it reads 100 ohms. Now put one meter lead on one end of the resistance wire and the other on the wiper connection. Rotate the switch from stop o stop, the reading should smoothly change between zero and what ever you read end to end, ie 100 ohms.

I have a NOS dimmer in the Fury that doesn't work right, probably why it lived on someone's parts shelf so long. A year or so ago @CanCritter gave me a mint looking spare he had and unfortunately it looks NOS but doesn't seem to have a connection between the wiper and the resistance coil. If you don't mind, hang on to your dead ones for me and I'll try to rob parts and rebuild one or both of mine.

I’m sure I can help you out. So far I don’t know how many of mine don’t work. I would have to test them. I must have a half dozen gauge clusters and a drawer full of electric window switches and at least 3 of every dash switch that came in a fury 111 or sport fury. And my next project is stripping a 69 New Yorker. You wouldn’t need a perfect set of front fenders or doors (2 door) from a 69 N/Y would you ? Special pricing for fcbo members lol. I’m keeping the drive train. Everything behind the doors is Bad rust. Roof was vinyl so it’s pretty well gone as well. This car has the sentimental lighting option. oops sentinel light option lol

 

[Erayn]

I'm going to try to pull mine out this weekend and clean and test it. Thanks for starting the thread welder guy!

 

[Big_John]

$500 Canadian

???

I realize that you have some issues with shipping across the border, but how on earth does a $95 rebuild go up to $500?

67 68 69 70 Chrysler Newport 300 Dash Light Dimmer Switch Rebuild Service | eBay

 

[MrMoparCHP]

If you don't use the dimmer you can bypass the switch and only use it to turn on the dome light.
Outer two wires together.

Alan

 

[Welder guy]

???

I realize that you have some issues with shipping across the border, but how on earth does a $95 rebuild go up to $500?

67 68 69 70 Chrysler Newport 300 Dash Light Dimmer Switch Rebuild Service | eBay

I ordered a $50 dollar part from North Carolina had it shipped UPS. Paid with pay pal I paid pay pal with my visa.both of them take there cut in US dollars. Our dollar is only worth 72 cents once it goes though then UPS charged a brokerage fee , there was duties and then we have a what’s called a goods and services tax that’s charged on the total then our Provencial government seen fit to charge a carbon tax on everything. that jacked the price of everything that moves up here. Then when I thought I paid everything that Needed paying too UPS. They phoned and said they tried dropping it off at my house when I was at work and couldn’t drop it off so I had to drive 45 miles into Edmonton to there depot to find out they needed another 45 dollars for some more border crossing crap. The final bill for my $50 US part was $384 Canadian . I could have choked someone. So add on another $60 US on to the tab and you get to $500 Canadian in a hurry. It’s an absolute bargain for someone from the States to buy Canadian car or parts but a Financial horror story the other way around ! Whew now that’s a rant. Thanks for letting me blow off some steam. Didn’t mean to snap LOL

 

[Welder guy]

I'm going to try to pull mine out this weekend and clean and test it. Thanks for starting the thread welder guy!

I’m happy you joined fcbo welcome. The members here are great. They have a wealth of information. Even though ya drive a b body Lol It’s a Beautiful car !! Hope you get your thumbwheel dimmer switch repaired !

 

[Fury440]

I took a few pictures of the dimmer @CanCritter gave me. From the part number it appears to be OEM Mopar 1968-69-70 Charger GTX B-body Rallye Dash Dimmer
Don't know what is currently in the car.

In the parts list there are flavors depending on year and car line

Mine isn't in the parts list at all.

They all appear to mount the same so I expect the differences will be the wattage load, ie # of bulbs to be dimmed. I measured across the ends of my coil and found 25 ohms. The left pin connects to the brass button on the end of the coil. The center pin (R) connects to the wiper, when the thumb wheel is at the end that clicks, the wiper is resting on the brass button and the resistance between the center pin and the left pin is 0. When the thumb wheel is rotated the other way, the resistance climbs linearly from 0 to 25 ohms. The right side connects to a brass strip that will connect to the metal casing only when the slider is sitting on the brass button. This connection is made when the cam bump on the ceramic coil is rotated around. Not sure, but my guess is this pin connects to the door switch circuit which completes the ground path for all the courtesy lamps which a door switch will light when a door is opened.

 

[Welder guy]

That’s the same kind a switch I have I have a few of those used

 

[Welder guy]

I think I can help you out Fury440 and Erayn if you’re really stuck for a switch LOL I GUESS I’M A BIT OF A HORDER . You should see my sea can the shelfs are full of fury parts

 

[Erayn]

LOL I GUESS I’M A BIT OF A HORDER

Almost an understatement! Haha

 

[Welder guy]

This is the good stuff I’m restoring now. The first picture is taken though the restored speedometer plastic it turned out great it’s like glass. Then the air conditioning vents then the dash speakers are getting done. The install of the air conditioning is next winter along with everything else

 

[Welder guy]

Sorry I’m getting sidetracked here

 

[300rag]

Sorry I’m getting sidetracked here

It's your thread. Go where ever you want. We do the same.

 

[Big_John]

FWIW, the gentleman that rebuilds the dimmer switches in the link I posted rebuilds these window switches too and will take your old ones in trade for services.

 

[Fury440]

AFAIK a horder collects random mountains of misc junk, don't see any of that in your pictures, you are a connoisseur of all things Mopar!

You are also doing a amazing job on that car, I wish I had some of your talents!

Now that you've been suitably stroked ..... save me a dimmer and maybe a clock!

 

[Welder guy]

FWIW, the gentleman that rebuilds the dimmer switches in the link I posted rebuilds these window switches too and will take your old ones in trade for services.

View attachment 175360

Hummm now you have me thinking!!!