Workshop: Repairing Switches
There are lots of situations when you can’t lay your hands on a replacement switch for a particular job, because manufacturers don’t always use standard parts. In an ideal world, switches would be interchangeable, and you could pop into your nearest electrical supplier to get a replacement whenever something broke.
Unfortunately, we do not live in an ideal world, and you can almost guarantee that the spare part you need isn’t being made any more, or will have a three month shipping delay. I have a 14 year old imported Toyota, so I’m no stranger to this situation. Spare parts aren’t always available right off the shelf at my local auto suppliers, but in the case of a simple switch, it’s possible to refurbish the existing unit and save yourself the expense of a replacement part.
In this example, I will be repairing the mirror control switch from a 1994 Toyota Estima Emina, but you can use the techniques I describe here to repair almost any electronic switch. I removed this switch from the Estima because it would not let me adjust the passenger side mirror. I popped the switch out of the door panel with a Stanley blade, and disconnected the plug from the back of the unit. A simple examination showed the cause of the problem – the printed circuit board on the back of the switch was cracked and was not in contact with the switching part of the mechanism.
Like most switches, this switch was held together by plastic clips, and the PCB could be removed with a little gentle leverage in the right places. It pays to be careful when you are removing the back of a switch, because the contacts are often spring loaded and will fly out of the chassis if you aren’t expecting it.
With this switch, I was able to reposition the broken corner of the board and glue it back into place with epoxy. A close examination of the copper tracks on the circuit board showed that one or two breaks had occurred as a result of the cracked PCB. I repaired the cracks by removing varnish with a fibreglass pencil and soldering a piece of wire across the broken section of track.
I took the opportunity to check that all of the springs were in good working order. In this case they were, but if you find that you have a broken spring, replace it with whatever you have handy. I have brought electrical items from the Pound Shop in the past, so that I can take them apart to get the tiny springs.
Finally, I cleaned all of the electrical contacts and checked for corrosion. If any of the contacts are worn out, you can renew them using copper or aluminium tape. If the switch you are repairing has rubber buttons (like a remote control) then you can follow the advice from this article to refurbish them.
With the switching mechanism and tracks repaired, the next step is to reassemble and replace the switch in the original device. Give the switch a thorough test to make sure everything is working as it should be, and make sure that the switch doesn’t overheat or short out during use.