Homemade Fog / Spot Light Rocker Switch

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Tom Brearley
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Homemade Fog / Spot Light Rocker Switch

Post by Tom Brearley » Sun Jan 10, 2021 8:50 pm

Whilst we are mostly confined to our garages again, I thought I'd share my lockdown project.

I've had a fog light and a spot light fitted for some time, but the original style rocker switches seem practically impossible to find. None of the usual suspects, like Moss, make a reproduction and I have never seen an original one come up on Ebay. So I thought I'd try my hand at fabricating one.

The original looks like this, and according to the driver's handbook position 1 is Off, position 2 is fog light on with dipped beam and position 3 is spot light on with main beam.
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Last edited by Tom Brearley on Sun Jan 10, 2021 9:38 pm, edited 1 time in total.
1973 MGB GT
Mallard Green / Autumn Leaf

User avatar
Tom Brearley
Posts: 75
Joined: Sun Apr 01, 2018 6:54 pm
Forename: Tom
Surname: Brearley
Location: Devon

Re: Homemade Fog / Spot Light Rocker Switch

Post by Tom Brearley » Sun Jan 10, 2021 9:07 pm

Having looked and failed to find a 3 position, 2 circuits rocker switch in the original style, I needed to make my own. I started with an old light switch. It has 3 positions but is cumulative in operation. In other words position 2 is side-lights and position 3 is side-lights plus headlights. This isn't what is required for an auxiliary lights switch so modification needed.

There may be better way of achieving it, but my approach was to add a further contact and to blank off parts of the internal slider so that only two pairs of contacts would be connected at one time.

I made the extra contact by inserting a self-tapping screw through the top of the switch. Contact can then be made with the bracket on the edge of the slider.
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I modified the slider simply using masking tape. The slider can be thought of as having 6 possible contact areas (7 if you count the bracket). I blanked off 3 of them.
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Last edited by Tom Brearley on Mon Jan 11, 2021 7:49 am, edited 3 times in total.
1973 MGB GT
Mallard Green / Autumn Leaf

User avatar
Tom Brearley
Posts: 75
Joined: Sun Apr 01, 2018 6:54 pm
Forename: Tom
Surname: Brearley
Location: Devon

Re: Homemade Fog / Spot Light Rocker Switch

Post by Tom Brearley » Sun Jan 10, 2021 9:38 pm

I added a 'stationary' blade connector to the protruding part of the screw, and then sawed if off flush.

The 3 unmasked positions on the slider are gently centre-punched to compensate for the thickness of the tape.

Finally, I took a pic of the switch in the 1973 brochure, photoshopped it a bit and printed it onto a sticky label. It passes muster for the front of the switch - if you don't look too closely!

IMG_2149.JPG
1973 MGB GT
Mallard Green / Autumn Leaf

David Witham
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Surname: Witham

Re: Homemade Fog / Spot Light Rocker Switch

Post by David Witham » Fri Jan 22, 2021 8:37 pm

Fascinating project. I guess it would not matter too much if the fog light stayed on when the spot light came on.

JohnH
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Surname: Howard

Re: Homemade Fog / Spot Light Rocker Switch

Post by JohnH » Fri Jan 29, 2021 5:32 pm

I used a similar trick to change a lighting rocker to one for my upgraded two speed heater fan. The logo had worn off already. Clipped off unwanted tabs too so no future confusion.

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