Combination / headlamp switch repair

Growlerbearnz

Administrator
Staff member
Reposted from Delica.ca, original writeup by Falco.

... It is a simple switch, complex in style but simple, none the less. The images in this posting were taken with cell phones in dubious light conditions, my apologies for poor quality.

There is a small carriage that slides back and forth. It is controlled by a little thingy that is controlled by the rotating switch at the end of your wand. It turns the running lamps and the headlamps on and off. When you turn the switch at the end of the wand, the little thingy at the other end of the shaft pushes the little carriage back and forth. The little carriage has two copper contacts that connect to the contacts on the back of the relevant PC board. They look like this:

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Now you can see in the picture that what has happened is the contacts have gotten dirty over time, this dirt has helped to generate arcing (as indicated by the burn marks). In my case the arcing caused the switch carriage to fuse to the body and the wand pivot to do the same, which was the smell I experienced whilst driving. Let's look at the wand:

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As you can see the wand has a protruding ring, on the end of the ring is a tube that holds a spring and a ball bearing. As you move the wand to make a signal the ball bearing goes over bumps in the track. The pivot for the wand is under the metal plate, close to the switch carriage, which is why it got fused, as well, in my experience.

When the fusing happened it changed the molecular structure of the contact plate ~ it was no longer copper but had become a new alloy, created by heat.

There is a magic coating that goes on these contacts. This coating does a number of things:
  • It cleans the surface of the contact.
  • It enhances the connexion.
  • It also reduces or stops the arcing between the contacts.


Here is what I did:

First I had to get to the contraption in the first place. Underneath the steering wheel, by your lap as you sit in the seat is a small Phillips screw; this secures the horn control to the top of the wheel, you need to undo that first. Once that is out of the way, you push/lift the horn control forward, like this:

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You see the tab with the hole is where the screw goes in; the two forward tabs secure the unit via fixed leverage. Next, the wheel has to come off. This is done by removing, I believe is a 17mm nut (if it is not I'm sure you can work it out):

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Now that that is away you need to mark the position your wheel is at so you can put it back in the same direction on the spline:

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The wheel should slide off. I have heard that some people have experienced difficulty in removing the wheel, I have found that by not trying too hard it comes off easier. This is what you should see next:

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Next you must remove the casing about the steering column; this involves six Phillips screws from the underside:

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The under piece should fall off. For the top piece to come off requires the steering column to be in the down position, which is done by moving this lever:

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Now we get to the combination switch. To get it off so we can work with it you need to remove two screws:

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Now they are removed, gently pull the switch unit off of the steering column and turn it upside down. here are two more screws and a plastic clip to disconnect:

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Next is the contact plate which is held on by three screws and a "tongue in slot" arrangement. This plate reveals the switch carriage and contact plate. Note the "tongue" at the top of the plate in the second picture:

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The switch carriage comes out easily (when it's not welded to the body) and looks like this. Beneath it you will see the "thingy" that moves it back and forth:

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This is where the magic starts. I found this product called "Deoxit" at RP Electronics on Rosser Street, in Burnaby. It comes in different formulas ~ get the 100% concentrated version. This diminutive tube cost me nine bucks:

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You administer the "Deoxit" to the contacts. As I mentioned earlier it is a cleaner, you need to clean the gunge from and around the contacts. Having done that I re-administered the product and let it dry. It doesn't take a lot:

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Then you put it all back together again and drive along your merry way!

Will this help you in your particular situation? I'm not sure. I think this will help a little, 'though ~ This experience has be very enlightening, to say the least. It also has given me a sense of ability and achievement. I did it! And... I got out of the Tardis Motel backyard around two in the morning. I really must extend my heart felt gratitude to Jay who was near by or actively working with me. You are a good teacher, Jay, and a good friend.

Falco.
 
An addendum: the squarer contact develops a notch in the front edge where it runs into and over the button contacts on the PCB. If you turn the contact around, you'll get another 25 years of service out of it, and the switch will feel like new!
Switch1.JPG

Here's the nasty old carriage (upper) and a clean one with the contact reversed (lower).
switch2.JPG
 
Further info from Morganizer:

On the way home my dash lights didn't go on when I turned on the headlights. Uh oh.

I checked the forum and found this post. Good info that if the dash lights don't go on and the tail lights don't go on, it's probably the Combination Switch. Followed Falco's post and got it working again. Here's what I'd like to add, based on what I did:

- Start by removing Horn 15A fuse. This prevents the horn from sounding while you're working on it, and makes sure there's no current supplied to it in case you *OUCH* Dang!...
- The screw for the horn is 'captive' -- don't turn and turn and turn waiting for it to fall on the carpet because it ain't gonna.
- Notice that even though the wire for the horn appears to be screwed on, it's a spade connector and you can just unplug it with your fingers, and set the horn aside. So it doesn't go flying when you pull the steering wheel off.
- Unplug the wiring harness for the Combination Switch. Just follow down the steering column, and it's the big one. Don't unplug the small one, because if you do, the "door ajar" beeper will sound continuously...the whole time you're working on it. Unplugging the harness ensures there is no current that will flow in the switch in case you *OUCH* Dang! Not again...
- Remove the harness from the car and do the rest in good light on a workbench, if you have the luxury. Cable ties are the un-doable/re-doable kind, just pry the little release tab, and you can put them back on after.
- A brass scratch brush and some Scotch Brite do a great job of cleaning the contacts.
- Make note of the position of control stocks and reassemble switch with them in the same position as when you took it apart. I think this one, you get away with it, but but this is good general practice with these things.
- On the workbench, stack wooden blocks to support the Combination Switch, so you can work on the back without the control stocks keeping it from laying flat.
- The plastic ring that cancels the turn signals when the steering wheel turns. One of the three pins has a little arrow pointing to it. Make note of its orientation (?!) when you take the wheel off, so you can put it back the same way. I think it goes to the right, opposite the mechanism it trips to shut the blinkers off <-- CONFIRMED!. I'll know next time I drive if I'm out to lunch on that one. [it worked so well, I kept forgetting I was supposed to be testing something that had been taken apart] It would be nice if they had a matching arrow on the steering wheel. You could draw one with the same pen you used to mark the spline. What you didn't?! Uh oh...

While I had the Combination Switch on the workbench, I figured the Turn Signal switch and Wiper switch are going to start acting up soon, so may as well take it apart and clean those too. Sure enough, it was filthy in there, cleaned it all up. Got the whole thing back together and the right turn signal didn't work! The copper contact for the signals is held into the plastic slider it's in (which mercifully only fits in the track one way) by a little tab in each end. Push in on that, and you can remove the contact for better cleaning and to stretch the spring, as someone else recommended on this thread. Did that and reassembled it all and now I'll get that warm, fuzzy feeling every time I use the Combination Switch.

Also note in Falco's post, he's wearing nitrile gloves. That's a good idea. I kept thinking, "It's electronics, it's nice clean work." But I went through a lot of Gojo. Those parts get pretty grubby. Hence the need to clean the contacts...
 
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