DIY - Rebuilding the headlight switch

Ok friends, here's another edition of kitchen table restorations, except tonight my wife has kicked me out of the kitchen so I will be cluttering up the back deck table while enjoying some vino. Anyway, these expensive switches can be rebuilt quite easily. This is my friend's switch, I noticed that when I turned the parking lights on it started to emit a little smoke so time to rebuild, I did mine a few years ago.

Pry away the corners where the aluminum case is crimped, first with a tiny screwdriver then a little bigger one to free up the plastic top, try not to destroy the metal too much as it will be re-crimped later:

Then as it starts to release, ease the pieces apart, a corner or 2 may need some more prying:

Off it comes, 2 of the prongs stay behind:

Top off and lots of crusty gunk:

Important to note the contact layout for reassembly:

Pull out the slider piece:

Caution: springs abound: total of 6 small and 2 large in the entire switch, 4 for the slider top:

Bottom side has 2 plastic pieces that fit into the indentations in the case plus the 2 large springs:

Pull the reostat unit out in one piece, be careful as it is spring loaded and keep holding it together while removing because it will want to fly apart:

All clean with 45 year old grease removed and all electrical contacts sanded with uber fine grit, reostat coil cleaned and lubed with some spray electronic cleaner/lube:

 

[Stevehose]

After a week of wiper motor guts strewn about on the kitchen table, along with the wiper arms (repair of little locking tab on one) and linkage for cleaning/greasing, plus my friend's tool kit contents for cleaning, I agreed to take my act outdoors. Only a temporary spousal gesture, as the table is now clear and ready for the center grill slat removal/black paint job this weekend.

+1, I prefer the kitchen/dining table "workbench"...then the resultant abrogation of your access to inside the home for another one of your projects....wait a minute, it that why you were out-of-doors on this one?

 

[Frankie123]

Thanks for the thread Steve. Gave me the confidence to tackle the disassembly and re-assemble correctly.

Great pictures

 

[ECA90049]

Great to know it can be fixed. I can't turn off my running lights and am thinking it's the headlight switch. With your instructions I'm inspired to try and fix it myself... the first step will be to figure out how to remove it from the dash (any tips? I'm just now getting into DIY repairs on the e9).

 

[Ohmess]

Removal is pretty simple. Unscrew the knob, and then you will see a plate with slots on either side of the shaft. Use a pin spanner wrench or a small needle nose pliers to unscrew the plate and the switch comes out the back.

 

[ECA90049]

Removal is pretty simple. Unscrew the knob, and then you will see a plate with slots on either side of the shaft. Use a pin spanner wrench or a small needle nose pliers to unscrew the plate and the switch comes out the back.

Thanks, gonna give this a go...E

 

[Frederick]

Reassembly:

2 little springs into the plastic piece, these will provide tension for the metal contact piece against the reostat coil:

Metal contact piece, one spring fits on a little mound on the piece, the other spring presses on the reostat arm:

Lay the plastic spacer on (my apologies to DQ for my spray-paint stained thumb):

Then the metal plate:

Pinch it together then slide it into the housing, the little indents in the case walls and the tabs of the metal plate which fit into the bottom of the case will hold it in:

Grease the bottom and insert the pull rod, the cutout on the rod is what the center of the slider piece fits over:

Insert the 2 large springs into the bottom of the slider piece and install the 2 plastic cones:

Turn the switch on its side and install the slider piece over the cut out in the center of the rod so that it locks on the rod, then reinstall the 4 springs and the contacts (note that the horizontal contact piece is on the top side as the rod exits the housing to the left):

Install the top and crimp over the plastic whatever is left of the case corners so that it is held back together agin:

Apply JB Weld (how I love this stuff) where the 2 halves meet (there may be a small gap to work some in) as well as the corners to reinforce what's left of the aluminum:

Clean it up and zip tie it closed for a day for the JB to dry:

Once zip tied you can test the movement/function of the switch while the JB dries. It will be good as new with a nice crisp action and solid "click" as the lights are switched on. And perhaps the reostat will work once again.

Thanks for the demo, Steve, just finished mine, used cryo- with instant spray to seal it.
The plastic was very brittle. but it works great. Won’t know totally for sure until I test it on an automobile.

 

[Stevehose]

used cryo- with instant spray to seal it

What is this you used? Glad the pics helped.

 

[Frederick]

Sorry, Cyanoacrylate, better known as superglue. I use the Mohawk brand with an activator. Instant adhesion . The activator is great for holding things in place say temporarily while you concoct something permanent say with the JB Weld or two-part epoxy.