51 Pontiac Chieftan Light Switch

[51UKChieftan]

Hi Guys,

 

Is possible to repair or replace the rheostat on the light switch? 

 

Joe 

[PONTIAC1953]

yes, I've seen nos rheostats listed on feebay

[51UKChieftan]

Thanks, Nothing on there at the moment 😒

[PhilAndrews]

On 3/30/2023 at 9:34 AM, 47FordCoupe said:

Hi Guys,

 

Is possible to repair or replace the rheostat on the light switch? 

 

Joe 

What's it doing? 

 

The contacts get dirty and they get flickery. If it's burned out then that's more awkward.

 

By now the switches and rheostats need a good clean and grease.

[51UKChieftan]

Hi Phil,

 

It works on the lowest setting but the slightest movement it stops working. I then have to "twiddle" it and eventually it will come on again at the lowest setting. Anything above low and nothing will happen no matter how much "twiddling" is involved.

 

Regards

 

Joe

[PhilAndrews]

If it works on the most dim, the resistance wire is good, the sweep has two detents (formed by two rivets), one at the most clockwise is connected to the sweep arm and shuts the panel lights off completely. Fully counter clockwise is the rivet connected to battery power (or swapped round but connected both ways work the same). If you cannot feel those detents, nor does twisting the knob give a slight "raspy" feel, the sweep arm is likely making poor contact.

It is spring loaded but a very simple mechanism and open to dirt and dust getting into it, which can cause the spring to become ineffective.

 

Have you taken the switch out yet? (Also, do you know how it comes apart? It took me a while to figure out, is all)

Edited April 5, 2023 by PhilAndrews (see edit history)

[PhilAndrews]

The rheostat is assembled like this. 

Plastic top-hat on the left holds the spring in place and also acts to insulate the wiper arm from the frame. That sits on the connector to the left screw lug (not pictured), which is held in with a rivet. The resistance wire attaches to the other end of the sweep but it's not connected on the far end (that connection is performed only by the sweep arm). That all then fits into the ceramic.

 

The connection between the center plate and sweep arm can get dirty, as can the sweep arm to the resistance wire. A good clean might get it working again. I used electronic cleaning fluid (deoxit) and added a little dielectric grease (sold as light bulb grease) to prevent further oxidization.

 

Note that I didn't take it apart, only got inside with a wire brush, using a tool to push the wiper arm up. Diagram is to try help understand the mechanism.

 

Edited April 5, 2023 by PhilAndrews (see edit history)

[Andy J]

I might try that with mine. I have thought about spraying it with the electronics cleaner that you mentioned Phil. Mine works but as you turn the knob the dash lights go off,turn it a little more they come on again,off again,and so forth. I think a good cleaning will definitely help it.

[PhilAndrews]

On both the ones I have, the brass had formed a layer of verdigris on all the brass parts, which is very hard. 

Cleaning the wiper arm, the resistance wire and the rivets with a steel wire brush yielded the best results. 

I find the least reliable portion of the sweep to be fully counter clockwise where the sweep arm sits the nub that makes contact with the resistance wire into the dimple of the rivet, making contact gently where the corrosion isn't burnished off with use.

I'm sure a glass-fiber brush would also work to clean the surfaces up.

 

Phil

[51UKChieftan]

Hi Phil,

 

Thanks for the information Phil, the photo and diagram help a lot. I haven't removed it yet but i am planning to do it this  weekend. I believe it removes in a similar way to the one on my 57 Caddy. I remember i struggled to find the location of the release lug/button to remove the switch lever on that.

 

Thanks again, very much appreciated.

 

Regards

 

Joe

[PhilAndrews]

5 hours ago, 47FordCoupe said:

Hi Phil,

 

Thanks for the information Phil, the photo and diagram help a lot. I haven't removed it yet but i am planning to do it this  weekend. I believe it removes in a similar way to the one on my 57 Caddy. I remember i struggled to find the location of the release lug/button to remove the switch lever on that.

 

Thanks again, very much appreciated.

 

Regards

 

Joe

Correct. Release button is arrowed.

Edited April 6, 2023 by PhilAndrews (see edit history)

[51UKChieftan]

Thanks Phil,

 

I didn't get round to it over the weekend but will hopefully get onto it this coming weekend. Picture is a great help, it helps to avoid all the fumbling around in a restricted space.

Regards

 

Joe

 

[51UKChieftan]

Hi Guys,

 

I have found the issue and it is a broken rheostat. Pic attached. 

Is this repairable or should i just jump it from the tail light. If jumping is the best option for now which two terminals do i use

Thanks

Joe

[PONTIAC1953]

I have seen nos and nors rheostats listed on feebay, currently there's also a nos complete headlight switch for 49-54 Pontiacs.

[51UKChieftan]

Thanks Pontiac1953,

 

I will have a look at that. I would rather repair mine if possible as shipping to the uk is extortionate on many items, in some caeses paying more for shipping than the part! ☹️

 

Regards

 

Joe

[PhilAndrews]

I'm headed to the UK on the 20th, ship one here in the US and I can bring it and mail it on?

[51UKChieftan]

Hi Phil,

 

Thank you for the offer, it is very much appreciated.

 

I have tried locating an NOS light switch but with no success.

 

Thanks again

 

Joe

[PhilAndrews]

No worries. If you find one and they won't ship, I can act as middleman if you need.

[51UKChieftan]

Thanks Phil.

 

Really appreciate that.

 

What part of the UK are you visiting?

 

Joe

 

Edited May 18, 2023 by 47FordCoupe (see edit history)

[PhilAndrews]

11 hours ago, 47FordCoupe said:

Thanks Phil.

 

Really appreciate that.

 

What part of the UK are you visiting?

 

Joe

 

Southwest, down near Bristol.

[51UKChieftan]

Nice part of the country.

Enjoy your trip.

 

Joe