Refurbishing a light switch

[jagnut66]

Hi,
With the battery back on to iron out any electrical gremlins I found with a little persuasion everything came back to life.....
Except one.
My light switch refused to illuminate when in the sidelight position. No sides, no rears, no numberplate.
Switched to headlights, the headlights & main beam only worked. Still no sides, no rears, or numberplate.
So I bought a new one and fitted it.
Now they were permanently on!......
Faced with the possibility that I might get a replacement only to find the same problem, I chose to investigate.
The switch itself comes apart fairly easily. Unscrew the small brass retaining screw on the underside (picture 1) and the screw at the other end (nut and washers on original switches I found), (picture 8 ). On my original there is also a fibre cover plate to be eased off before I could get at that end of things.
Then withdraw the main control arm after teasing the contact ring and the insulation its mounted on off / out the other end first.
The switching control arm can be shaken out the side and into your hand and reinserted via the side slot when putting it all back together (picture 5). The one on my original switch needed a clean up.
The control ring pushes back on with the exposed section of the insulation face down, so that when in the off position the brass isn't making contact.
The hole in the middle isn't round, more oval, to aid with locating it on the arm after it's been reinserted. Once located it can be pushed firmly home.
Note the little button that holds the Bakelite knob in place needs to go back facing downwards, the same side as the flat section of the threaded part that pushes through the dash to have the retaining ring screwed over it.
The problem I found with the new unit was that, unlike the original unit where the brass part of the control ring was fitted neatly flush to its insulation mounting (picture 3), on the new one the slot it sits into on the insulation is different and it is 'crimped' in place, allowing it (if done badly) to be in permanent contact with the contact arms (picture 4). With a little recrimpimg (squashing) this was rectified, although the new switch still requires a little 'tweak' when switching up or down through lighting positions, I now have illumintion in both positions and when it is off, it now is off.
However, pulling the new one apart did have one positive aspect to it, in that I thought that, if I can disassemble the modern replacement easily enough, how hard can it be to disassemble the original and clean it up.
Hence the point of this post, as I thought I'd share how easy it is with everyone on here (who hasn't done this already).
The pictures show the components after the attentions of wire wool, wire brush and screwdriver, removing decades of grime and grot.
I am hoping that I have now restored the original to working condition, though I have yet to test it.
Please note that the names I've used for the parts are my own descriptive terms, if they have 'official' names I'm not aware of them.
Here's hoping this will be of some use to someone.
Best wishes,
Mike.

1 First slacken off screw.JPG (414.97 KiB) Viewed 3812 times

2 Switch in bits.JPG (1.04 MiB) Viewed 4429 times

3 Control ring cleaned up.JPG (500.24 KiB) Viewed 4429 times

4 Contact arms cleaned up.JPG (562.71 KiB) Viewed 4429 times

5 Reinserting cleaned switch locating arm.JPG (561.69 KiB) Viewed 4429 times

[jagnut66]

6 Reinserting switching control arm.JPG (541.23 KiB) Viewed 4426 times

7 Control ring being reinserted -- brass face up -- bakelite (no contact) face down.JPG (258.76 KiB) Viewed 4426 times

8 Back together -- fibre washer first, brass washer second, then the nut.JPG (521.41 KiB) Viewed 4426 times

9 Fibre cover plate going back on.JPG (626.63 KiB) Viewed 4426 times

10 Sole surviving brass retaining pin for cover plate.JPG (76.15 KiB) Viewed 4426 times

[jagnut66]

11 Pin glued in place.JPG (615.14 KiB) Viewed 4426 times

12 Refurbished switch complete.JPG (807.92 KiB) Viewed 4426 times

[jagnut66]

PS: The size of the socket I used to remove the nut on my original switch is 5mm (3/16").
Best wishes,
Mike.

[geoberni]

Well done Mike.
A good tutorial.
I've dismantled similar items in the past and the technology of the era is pretty consistent.
I've got a suspect faulty one in garage somewhere that I need to look at.
It was in a box of odds n' ends that was in Basil's boot when I picked him up 9 yrs ago.
I just need to remember where I put it...

[MikeNash]

Thank you Jagnut66.

May I add a bit re the current these switches can safely handle? Finding a pair of old spotlights, I stuck them on the front and wired them via the "bullet" style connectors into my existing wiring to see how they'd work, the spots being wired directly so they always came on with the main beams. (The idea being that when I wanted full light, I got it.) This meant that there was some 190 watts up front i.e. say about 14/15 amps flowing through the light switch. (And, of course also through the dip switch.) I never got round to fitting relays and the system worked successfully for years. And the lights were far better than My Manager's string of modern cars.

Regards from MikeN.