Servicing your lighting switches etc, discussion not problem

An alchemy of sparks, copper wire and earth

Moderators: User administrators, Moderators

Post Reply
User avatar
ghost123uk
Registered user
Posts: 6855
Joined: 10 Mar 2006, 10:15
80-90 Mem No: 2585
Location: John in Malpas, in the very S. W. part of Cheshire.
Contact:

Servicing your lighting switches etc, discussion not problem

Post by ghost123uk »

I got asked this in a pm, and thought I would share my thoughts on it.

Hi John
There seem to be loads of products on the market for cleaning electrical switches. Have you got a recommendation for the best one for light switches like the ones in our vans? Cheers.

OK, firstly I must say that in my experience (40+ years), "Switch Cleaner" as we generally know it is very little help when it comes to "servicing" 12 Volt lighting (etc) switches. Most of the stuff you can buy (Servisol, Maplins etc) is NOT designed to do much at all to the relatively heavy contacts found in normal automotive switches. It is designed to "service" the likes of volume controls (etc) on Hi-Fi systems etc, where it cleans the delicate carbon track and coats it in lubricant that is especially geared towards carbon tracks and the associated brass "wiper". It can be effective in delicate multi-contact switches (as found in Hi-Fi etc) to a lesser extent.

When you consider what goes on inside a 12 Volt lighting switch though, one can see why it is of little use (imho). We have some fairly heavy duty lumps of brass that make a firm contact with each other via a spring. These contacts "arc" a little every time they are used, much like the rotor arm of a vehicles distributor. This arcing causes both erosion of the mating surfaces and a build up of pretty solid / crusty carbon deposits. In my opinion, no spray is going to do much to help rectify either of those two symptoms of a dodgy switch (of that type).

I have also personally seen Servisol virtually dissolve certain plastics (I once ruined the plastic jack plug sockets on a guitar foot peddle with the stuff), so I can't recommend that (other than for most volume potentiometers).

If I was going to spray something onto 12 Volt vehicle switches, it would likely be this = "DP60" on Ebay, but in reality, if I had a suspicion a switch needed attention, I would either strip it, clean the contacts by scraping them and lubricating the moving parts with a light application of Vaseline or simply replace it.
Got a new van, but it's a 165bhp T4 [shock horror] Accurate LPG Station map here

dave friday
Registered user
Posts: 804
Joined: 15 Oct 2006, 11:19
80-90 Mem No: 5533
Location: rambler de oria, near albox,almeria,spain

Re: Servicing your lighting switches etc, discussion not problem

Post by dave friday »

Well...fitting a relay next to the [dodgy] switch is one way,maybe a high current mosfet [used as a switch] but you'd have to find a way to bias the gate [a couple of transistors etc]
But quite a lot of work when you can just replace the switch [as you say]
I like the "on"resistance of 0.025mohm of the sud45po3-15a mosfet compared to typical switch contact resistance of 0.3 to 0.5ohm!
And yes I have been doing some reading...
I dont think, so I'm not[do I exist?]
1992 1600td [ jx ] syncro panel van[leisuredrive camper ]

User avatar
CovKid
Trader
Posts: 8411
Joined: 30 Apr 2006, 13:19
80-90 Mem No: 3529
Location: Ralph - Coventry (Retired)
Contact:

Re: Servicing your lighting switches etc, discussion not problem

Post by CovKid »

Trouble is, some switches carry more current than is ideal and whilst I'm not keen to keep using relays (yet more connections that can play up or fail) sometimes its the only solution. I tend to steer towards reorganising the layout first. The 6mm feed to the fusebox is a bit optimistic too :D
Roller paint your camper at home: http://roller.epizy.com/55554/" onclick="window.open(this.href);return false; for MP4 download.

dave friday
Registered user
Posts: 804
Joined: 15 Oct 2006, 11:19
80-90 Mem No: 5533
Location: rambler de oria, near albox,almeria,spain

Re: Servicing your lighting switches etc, discussion not problem

Post by dave friday »

I had a problem the tap micro switch ,fitted a relay,bingo!
The pump draws a fair old current !
I dont think, so I'm not[do I exist?]
1992 1600td [ jx ] syncro panel van[leisuredrive camper ]

User avatar
ghost123uk
Registered user
Posts: 6855
Joined: 10 Mar 2006, 10:15
80-90 Mem No: 2585
Location: John in Malpas, in the very S. W. part of Cheshire.
Contact:

Re: Servicing your lighting switches etc, discussion not problem

Post by ghost123uk »

Of course we could go solid state switch route as dave friday suggests above, in fact we could re-wire the whole van and go down the CANBUS route that some modern cars use :twisted:
:run
Got a new van, but it's a 165bhp T4 [shock horror] Accurate LPG Station map here

User avatar
marlinowner
Registered user
Posts: 1530
Joined: 28 Jan 2014, 12:02
80-90 Mem No: 13646
Location: Scottish Borders

Re: Servicing your lighting switches etc, discussion not problem

Post by marlinowner »

Best way to clean switches is to use them.
1993 SA VW T25/T3 2.5i Microbus/homebrew camper
1981/1968 Marlin Kitcar TR6 Engine

Jeff J
Registered user
Posts: 648
Joined: 02 Jul 2012, 07:12
80-90 Mem No: 13853
Location: Millom Cumbria

Re: Servicing your lighting switches etc, discussion not problem

Post by Jeff J »

I always use De-oxit, but I am not sure it is available in a spray can.

Post Reply