Combination Switch Or Headlight Switch Exposed!

OK........I did a little write up over at MT on the Headlight Switch (HLS) that seems to go bad on our 1986-1993 Mazda trucks. The HLS is mounted to the Combination Switch and when it goes bad, most of your running lights won't turn on when you have the headlights on!

So here is the fix for it.......I pulled my whole CBS out but you may be able to just remove the HLS from the CBS and not have to pull the steering wheel this way.



The combination switch (CBS) is the switch that is directly behind the steering wheel on our 86-93 Mazda trucks, and has the turn signal/headlight switch/high & low beam switch lever that sticks out of it on the left side.
Sometimes, something in this area of the switch goes bad and your parking lights, or headlights, or both won't work all of a sudden.
Well, my latest truck had this problem........none of the lights would come on when you rotated the light switch to turn on the parking lamps. The HL would work when they were turned on, but no running lamps nor dash lamps. Luckily I had a spare earlier model switch (this is a 1986 B2000) that had the 4 wire connection as opposed to the 5 wire setup switch.........there are 2 different ones.......and here they are.
You can see there are 2 different headlight switches with these CBS's.........the 4 wire plug one is usually a white back one and the 5 wire one (it's actually a 6 plug connector, but one is not used) is mainly black on it's backside.

The white 4 terminal one.

Credits

Created By: axel breaker earl

axel breaker earl   +1y

NOW.......to see what makes this HL switch work, I pried the 3 tabs that hold the back of it to the front of it, and here is what I found!

There are 3 "points" in there that allow the parking lamps & dash lamps to turn on, the low beam HL's to turn on, and the high beam HL's to turn on! You can see that they are pretty nasty looking after arcing on and off over the last 27 years!

There is also the switch for the hazard lights too, with some burnt up grease on that as well.....

There are 3 "pins" that rest on the long copper arms of those 3 points when these 2 pieces are snapped together and those hold the 3 sets of points OPENED when the lights are turned off.

Flipping this 'black part' over, there are 2 areas where the ends of the turn signal arm slips into and they control the position of those "pins" to turn the lights on and off.

Ends of the turn signal arm....

axel breaker earl   +1y

When the HL switch is split apart, the black side can then be further taken apart to see how it controls those 3 pins when the lever is rotated or pushed back or forward.

That area where the turn signal lever ends engage, can be slipped off to show the other side of the small plastic pins that push on the points arms to hold the points opened.

These recessed channels lets those plastic pins go down when they land in a recessed area and therefore lets the points close to turn on the headlights, high beams or parking lamps!

That piece can also be slid apart into 2 different pieces because those turn signal lever ends move in different directions to each other.

Here it is just sitting up on the black part of the switch to show how it would lay down in there........except it actually "slides" in from the right side.

axel breaker earl   +1y

Here is the "pin" area of the switch with the pins removed.......

there are no small springs behind the plastic pins because from where they rest on the long copper arms of the points, the copper arms actually keep them spring loaded as the "at rest" position of the points are a closed position.....they are set to have tension on them to stay in a closed position, and the pins actually hold them opened until the switch is operated and it releases one or 2 pins at a time to allow the points to close and therefore the lights to turn on!

It's that simple! LOL, I know it's hard to comprehend all of this, but the bottom line is.......the points get dirty, and probably the tension on the parking light points arm gets weak, and it adds up to the points on the parking light circuit not making good contact........that's it!

AND, the switch is nearly fully repairable and can be cleaned and put back together to give years of service again! I will show how I cleaned it all up and put it back together again......and in the next day or so, I will hook it back up to the truck and make sure it works again, but I am 99.9% sure it is fixed!

A closer look at the points.....

axel breaker earl   +1y

Here you can see which points control which lights...

The points are actually removable and can be cleaned very easily.

You can also see where the pins rest on the copper arms, as they have left an imprint there where they ride.

You can also see that the parking lamp points (far right) have gotten hotter than the HL points........the copper arm has turned color near the end of it where the points are.........probably from resistance (dirty points) or from too much of a load.......but I would think the headlights draw more current than the total amount of the parking lamps that are on when the points are closed.

The 3 sets of points and their copper arms can be removed to clean them good.......

axel breaker earl   +1y

Cleaned and ready to go back together.

Setting the points back in place.

I just slightly bent the parking lamp point arm to help put a tad more pressure onto the other half of it's point so it is guaranteed to make good contact when it is in it's closed position.

Then after you place the pins in their bores, it is just a matter of snapping the 2 halves together and then aligning the turn signal arm ends to the respective areas on the HL switch, and screwing it back in place.

If you remember the brown greasy area for the hazard switch..........on the left in the pic.......

.........when I first unsnapped the 2 halves of the switch, I cleaned that area real good and re-lubed it with Sil-Glyde Brake Lubricant........it doesn't get runny with heat, and I think it is perfect for the lube inside of an electrical switch.

axel breaker earl   +1y

Here's a couple more pics of the switch......as if there ain't enough already! Kinda different angles of it before it gets snapped back together.

It was not done yet in this pic, but the right side of the picture is one area that I used the Sil-Glyde lube.......I put a generous amount on those copper tabs off on the right........NONE on the points arms or tips!

This end of the points arms are actually like the female end of a electric spade style connector.........this end pushes onto the male portion of the spade style connection.......so I crimped the female side just a tad so it was sure to make a good connection.

I should have flipped this over and taken a pic, so you could see what I mean!

So I think the main reason this switch was not working completely, is because of the dirty points on the parking lamp point. I could have just pulled the points, cleaned them, and snapped it back together again and it would work!