<VV> instrument lights

Doug Mackintosh dougmackintosh at yahoo.com
Thu Aug 17 16:20:05 EDT 2017

The dimmer is a contact against a semicircular resistor consisting of coiled tiny cross-section wire. One end of the resistor is connected to ground. The instrument light power goes to the contact which is attached to the knob. As you rotate the knob it moves the contact along the resistor. At one extreme of the rotation most of the resistor is in the circuit (hence lots of resistance and dim lights); at the other extreme only a short piece of the resistor is in the circuit (hence low resistance and bright lights). 
I have had Corvairs where the contact between the contact and resistor was hit or miss due to corrosion. The resistor wire is also fairly delicate and can break, therefore breaking the circuit. I had one that worked intermittently for months. I got pretty good at wiggling the knob just right to get the lights to go on; sometimes pushing the knob inward slightly helped.
Take the switch out and take a look (the resistor and contact are right at the front of the switch and clearly visible once you remove the switch). Test it with a continuity meter while you rotate the switch. I have been able to get one working in the past by some cleaning. Other times i had to replace the switch with a new used one.
I made some notes and a diagram which I have attached for what it is worth.
<<Date: Wed, 16 Aug 2017 16:57:17 -0400
From: Byron LaMotte <bhlamotte at gmail.com>
To: VirtualVair <virtualvairs at corvair.org>
Subject: <VV> instrument lights
    <CAN9cQMCS-u4Gr45bWVW=b4ayD+3b27KrXc+goqPvw=KjG-gXjQ at mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"

Last night my instrument lights went out on my 1964 while fiddling with the
dimmer on the light switch. I suspected a fuse but they look okay?

Byron (Brud) LaMotte
4501 World Farm Rd.
Oxford, Md. 21654
410-924-1311 cell>>

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