Friday, April 17, 2020

Lockdown Project: Flashing light

With plenty of time on my hands, I'm going to try to be motivated enough to work through a few projects that have been kicking around for ages. I don't know about you, but I'm finding staying focused on anything tough right now and have to resist the urge not to watch rubbish on TV when I'm not working.

Anyway, I have a flashing warning light that I picked up for a fiver at a car show. It attaches to your roof with a rubber sucker and has the hallmarks of a cheap 1970s or 80s accessory. Cheaply made, I'm sure it was sold as a safety aid if you broke down.

Tatty chrome and a busted battery box in the base seemed to be the main issues. While the chrome is beyond me, I reckoned the wiring would be fixable.

First job, remove the old box. No problem there, drilling out a couple of aluminium rivets saw the plastic bits and other remains removed and in the bin.


For some reason, power was to come from 3 D-cells. I wired one compartment out of a 4-cell AA battery box and connected it up. The bulb is a special old-style torch bulb that includes a flashing unit. I guess this is a bi-metallic device as part of the filament. I tracked a couple of these down on-line.

I was particularly pleased with my connection to the body - a hole drilled through a rivet and the wire poked through this with a blob of solder. All connected up, the unit worked, but not very reliably. I wasn't happy with the switch. Even afer a bit of WD40, it didn't seem quite right. Until it exploded.


Maybe exploded is putting it a bit strong, but falling apart into several pieces isn't as exciting, and the Interweb is all about excitement isn't it.

The rivets holding the switch in position were drilled out and I set to, to repair the slider with superglue, bracing the joins with the thinnest plastic sheet I had. This was glued and trimmed to shape later. Once happy, the unit was rebuilt with brass bolts. I did the connection to the case this way at the same time as there wasn't any point in trying to hide the repair any more.

A quick clean of the chrome with some Brasso and the lamp is ready for service. After a few seconds warm-up, the light starts to flash. It's a bit intermittent to start with but seems to settle down eventually. One day, it will live in the back of my Beetle as a decorative item. If I ever get the car back on the road that is - it's a bit harder to fix than this!

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