Instrument cluster lighting

[bbodie52]

I suspect that DIELECTRIC GREASE would work to improve those aging contacts on the Corvair light switch rheostat — or the switch could be replaced.

The rheostat in your light switch consists of a fixed wire coil resistor and a moving metal contact, or WIPER, that slides along the coil resistor to tap in at continuously variable points along the coil, which varies the resistance in the circuit to dim or brighten the instrument lights by changing the amount of electrical current flowing.

Most rear circuits route through the engine compartment multi-connector (below the voltage regulator, near the firewall). The number of metal connector pins inside depend on the Corvair model year, ranging from 8-12 pins. This rear multi-connector is a common source of trouble, as it is subjected to age, vibration, heat, and moisture for many years. Even when the outer plastic shell halves appear to be tightly connected, the internal metal pins may not be providing good electrical connectivity, as they may be loose, dirty, corroded, or bent.

https://www.amazon.com/Permatex-22058-D ... hdGY&psc=1
Permatex 22058 Dielectric Tune-Up Grease, 3 oz. Tube

What The Heck Is Dielectric Grease?
And is it necessary?
BY TONY MARKOVICH MARCH 2, 2021



https://www.thedrive.com/maintenance-re ... ric-grease

Part number C1332: 64-69 HEADLIGHT SWITCH

Weight: 0 lbs 10 oz
Catalog Page(s): 84B,R-37
Price: $ 23.95

https://ssl.corvair.com/user-cgi/catalo ... w_page=84B


Part number C1330: 60-63 HEADLIGHT SWITCH

Weight: 0 lbs 12 oz
Catalog Page(s): 84B,R-37
Price: $ 34.20

[66vairguy]

Brad - I do us dielectric grease on contacts, but I'm reluctant to use it on the dimmer rheostat wire as it is nichrome wire and it can get warm, ever hot. That said I've never measured the wire temperature with the lights dimmed. Not sure how warm the wire gets, but the wire is in a cerarmic holder!

Anybody ever bench tested the switch to see how warm the rheostat gets?

[Lane66Monza]

I would like to comment on the LED application and the housing color. I tried to stay as close to the Chevy color when repaiting the housings. The engineers had a reason for picking that shade of green to go with the lighting for night driving. So I found Rustoleum Satin Vintage Teal was as close as I could get for that purpose.

Rustoleum Satin Vintage Teal.jpg (12.48 KiB) Viewed 281 times

On LED bulbs, I bench tested white, green and blue bulbs in my 66 Monza More Door panel in my shop. I started with the single white bulbs, but with my shop blacked out these bulbs did not provide enough lighting in the panel for my tastes. The white and green 5 LED bulbs were too bright for night driving. The 5 LED blue bulbs were satisfactory for my needs in night driving. Definely easy on the eyes during night driving compared to the white dash lights. Same ble bulbs are being used in the Corsan panel going into my Monza Coupe. The green 5 LED bulbs did find a home in the Vairs. They are great for the heater controls panel lighting. The added light is needed in the area down there.

[Lane66Monza]

Brad - I do us dielectric grease on contacts, but I'm reluctant to use it on the dimmer rheostat wire as it is nichrome wire and it can get warm, ever hot. That said I've never measured the wire temperature with the lights dimmed. Not sure how warm the wire gets, but the wire is in a cerarmic holder!

Anybody ever bench tested the switch to see how warm the rheostat gets?

Take the switch out and ohm test the Rheostat. Use photo below for terminals to use. Terminls will be #2 and #3 to connect ohm meter to. Set ohms setting on ohm meter. Slowly rotate the knob clockwise watching the meter, then rotate counter-clockwise, then back clockwise. If meter reading is erractic or goes to infinity anywheres in the rotation, then you have a bad connection with the resistor coil to the wiper arm of shaft. Try to clean wiper arm contact area with a thin piece of 1200 grit paper and try meter reading again. If the contact is loose, then gentlely bending the wiper arm to get more pressure is an option. But after 50 years, a new switch might be needed, but get a reliable product. Not a cheap knock off that will have to be changed in a year.

[66vairguy]

Al -- I noticed the "WHITE" LED bulbs were bright and tended to "wash out" the orange needles. I fixed that issue by going with the "WARM WHITE" LED bulbs that emit a light color similar to an incandescent bulb. Now all the gauge and needle colors look good and have the proper contrast to make them easier to read at night.

[bbodie52]

Sat Apr 06, 2024 12:34 pm
Brad - I do us dielectric grease on contacts, but I'm reluctant to use it on the dimmer rheostat wire as it is nichrome wire and it can get warm, ever hot. That said I've never measured the wire temperature with the lights dimmed. Not sure how warm the wire gets, but the wire is in a cerarmic holder!

Anybody ever bench tested the switch to see how warm the rheostat gets?

The rheostat contained in the Corvair light switch serves to dim the illumination from between 5 to 8 small 3 watt instrument panel light bulbs (the total number varies between the Monza, Spyder, and Corsa instrument panels, plus the heater control and the Powerglide transmission shift lever control, if any). With a maximum current drawn by these bulbs no more than 24 watts, which calculates out to a total current draw of approximately 2 amps. A thin coating of dielectric grease would not be expected to have much insulating properties, and such a small capacity rheostat would be unlikely to get warm as it restricted a small portion of the current flowing to 8 or fewer small 3 watt illumination bulbs.

Dielectric grease is not an automotive necessity like oil or coolant, but it’s a popular product used in garages across the country. Most commonly applied on spark plug boots, lightbulbs, and battery terminals, dielectric grease is, in theory, a protectant like car wax. It’s not required, but it could help extend and maintain the life and quality of your vehicle and its parts.

Dielectric grease is just one of the numerous types of lubricants found in and around your automobile, and each one has a specific purpose. If you choose to pick up some dielectric grease, you can’t use it interchangeably with wheel bearing grease, or vice versa.

The Drive’s greasy editors are here to explain what dielectric grease is, isn’t, and how it’s supposed to work. Let’s start with the basics.

What Is Dielectric Grease?
Dielectric, sometimes referred to as tune-up grease, is a viscous non-conductive waterproof substance used to protect electrical connections from corrosion and dirt.

What Is Dielectric Grease Made of?
Dielectric grease is most commonly made of a silicone base and a thickener. It typically has a slightly translucent grayish or milky clear color. Permatex dielectric grease lists polydimethylsiloxane and silicone dioxide.

Although the dielectric grease does insulate the metal and wiring from external invaders, the contacts are tight enough to still maintain a connection, the grease is just displaced. That said, you do not need to squirt huge globs of dielectric grease into your connectors as you see in some videos out there.

Will Dielectric Grease Worsen a Connection?
There is a myth floating around that putting dielectric grease into electrical connections can cause them to fail because the grease gets between the metal. That’s not true.

When To Use Dielectric Grease
Dielectric grease acts as a lubricant, a sealant, an insulator, and a protectant when lightly used on these applications.

• Battery terminals
• Spark plug boots
• Bulb sockets
• Trailer connectors
• General electrical connections
• General plastic or rubber lubrication
  
  Q: So Does Dielectric Grease Improve a Connection?
  A: No, dielectric grease is not conductive, so it does not improve connectivity. It helps maintain a good connection, though.

https://www.thedrive.com/maintenance-re ... ric-grease

[Frank DuVal]

Welcome to the oddity of incandescent lighting with tungsten filaments. Tungsten has a lower resistance when cold, so it pulls more current at startup than operating. This is why they used to burn out more on turn on than while they were lit. So the colder (darker in this case) you run an incandescent bulb, the more current it draws. Now there is added resistance to the circuit in the rheostat, so a test would need to be performed to see just what the current to those #57 and #1816 lamps will be at full and reduced illumination. I'm probably overthinking this and the current will be less at reduced illumination anyway. In stage lighting it was a rule of thumb the power consumption was the same at all lighting levels except very dim, the rheostat being the hot part when the lamps were cold. The Variacs were much better at keeping heat and power levels down.

[66vairguy]

Welcome to the oddity of incandescent lighting with tungsten filaments. Tungsten has a lower resistance when cold, so it pulls more current at startup than operating. This is why they used to burn out more on turn on than while they were lit. So the colder (darker in this case) you run an incandescent bulb, the more current it draws. Now there is added resistance to the circuit in the rheostat, so a test would need to be performed to see just what the current to those #57 and #1816 lamps will be at full and reduced illumination. I'm probably overthinking this and the current will be less at reduced illumination anyway. In stage lighting it was a rule of thumb the power consumption was the same at all lighting levels except very dim, the rheostat being the hot part when the lamps were cold. The Variacs were much better at keeping heat and power levels down.

Welcome to the complex world of interactions of multiple components. Yes the bulb filament resistance increases as it gets hot, but with the rheostat in the circuit increasing resistance that limits how much the "cooler" bulb filament reduced resistance can increase amperage. Put another way the bulb grows dimmer and the rheostat gets hotter, but the total resistance increases limiting amperage. It gets complex and why engineering often relies on "close enough" formulas.

A good story for those pursuing a technical career is: "A scientist, a mathematician, and an engineer are asked "What is PI?" The scientists says "It is the ratio of a circle's perimeter to its diameter". The mathematical says "It is an irrational number because it can never exactly represent the fractional ratio". The engineer says "PI is about 3.14".

[MonzaMike]

UPDATE: I finally received my new switch. I bought a removal tool off eBay that was supposed to fit all Corvair light switches and cigarette lighters. It does not! I used needle nose pliers to unscrew the nut after removing the pull knob. I got the switch out. Lots of green. My new switch is visibly inferior in components but I put it in to give me time to properly clean and refurbish my old switch. Now I have dash lights. Thanks for all the help. This forum is awesome! Best by far of all the forums I’m on for various other endeavors.

[Frank DuVal]

You should have asked here about the tool (besides the very wide screwdriver I have used for years...). A club member makes them, Russell Davis, Blue Chip Tools.

https://www.bluechiptools.com/

You can buy them from him or Clarks.

He can tell you a lot about those that do not fit, hence why he started making them.

[MonzaMike]

Thank you. The eBay seller refunded my money so no harm. I may buy the blue chip before I decide to remove the switch(es) again.

[66vairguy]

Glad you got it working. Yes the NEW switches are not as "robust" as the originals. I do dismantle the old switches and clean the inner contacts and lube them with dielectric grease, BUT they were NOT meant to be dismantled and repaired. I break the Bakelite housings on about one out of five! Also sometimes the inner contacts are worn beyond being usable.

Note the ignitions switch bezel tools for sale often "chew up" the bezel. This is the only on I found that works well on LM cars.
https://www.ecklers.com/1966-1967-corve ... 551-1.html

Ecklers sells one for the three point bezels used on some 50's Chevy products.
https://www.ecklers.com/1955-57-chevy-i ... 560-1.html

[Frank DuVal]

Again, Russell Davis has seen the need and developed a Corvair ignition bezel remover tool.

https://www.bluechiptools.com/corvair-products

He also makes the early axle bearing removal tool and the remove the harmonic balancer or pulley without dropping the engine tool! Now he has added the install the rear seal easy tool to go along with the removal tool.

I know I sound like a Russell Davis promotional agent, but, he has been a CVCC club member for years and his products are designed for Corvairs. Working on our rusty eastern cars makes one develop tools and processes the west coast has not seen a need for...