Thursday, April 18, 2019

Series 3 Brake light switch

   Since I went with the disc brake conversion I use a Series 3 dual brake system and that includes a servo. With this set up the brake light switch is mounted on the pedal tower.

Mine went out, I know not when, I found out just doing a check.

I pulled the old one apart to see what went wrong and if it was repairable. AFTER I ordered 2 new ones from Rovahfarm. Part # 575166.

It appears that the switch has plenty of heat and the plastic melted and covered the contact. I don't know if this is the side with constant 12v. In the process I destroyed the switch as the brass is crimped over the plastic and I cut it off with a dremel tool.

Where the switch mounts;


What it looks like;


inside the brass looking at the contact ring;



Inside the plastic looking at the contacts;



The contact ring out of the body;



An exploded view;



A few days later;

Based on online advice I put a relay in the circuit. Now I just have to wait for the switch to show up.



I took power off the switch power wire and jumped it over to Terminal 30. I hooked the switch outlet(the control power) to the 86 terminal. the 85 terminal goes to ground with a black wire. The old switch outlet wire now comes off the 87 terminal.

To do all this I looked at my S3 workshop manual and can't find how to adjust the depth of the switch. This led me to pulling off my switch plate to try to figure out how it all works. I still don't know......

My manual just shows a flat plate, I have this;




Defender?  I used my dial calipers to check for movement of the switch lever and it is really small, .025. But then the switch doesn't move all that much either. I'll figure it out.

Welp, I got 2 switches and I figured I would have a spare. I didn't think I would need it so soon. The first one I tried would make the brake lights come on but they would not go off....

Here is one of the new switches;



Here I am showing the plunger open and depressed;




I used my test light to check the switch coming on as the brake pedal was depressed.



I was going to wire in a relay that you can see I mounted on the back wall, but it too would not turn the lights off when the pedal was released, so I went with the original wiring.

Now this story is not over, I have decided that the LR switch is too iffy and have decided to change my set up. I have ordered a pull-to-on switch that goes to a motorcycle rear brake. This will hook via a spring to the brake pedal in the footwell and replace the push-to-on switch at the top of the pedal. Motorcycle rear brake switches are durable as they are made to be in all kinds of weather and cycle for thousands of  brake applications.

Update May 2019;

    I did not waste any time I didn't want this switch to fail without me knowing. So I ordered the same rear brake switch as on my 2008 Suzuki DL650 Vstrom.  I found good pricing online at Babbitt's Online. I purchased a switch # 37740-31D00 and pull spring #09443-06012. with shipping @$36.
   They came yesterday and as I was busy with the NATO can carrier it put it on today.

Here is how;

    starting with seeing how it fit in the area and what type of bracket I would need and where it would attach;


    I figured I could go off the single bolt for the pedal box with a 90° angle of some 1/8" x 1" flat stock. The switch has an adjuster nut that presses into a hole in the brake pedal bracket on the bike. So I drilled a 5/8" hole in the end of some flat.


Next I figured out about how far away I need to bend the 90 and then drilled a 5/16" hole further than that for the bolt. Put it in my vise and hammered it over to a 90. Then cut off the excess which I left a little long in case I needed to move the switch farther away with more holes. Then test fit and see where to run the wires, the switch wires were easy in the next pic you can see an oblong hole in the parcel tray lower, I planned to use that.



I needed to get the 2 green wires in the next pic thru the bulkhead where the 2 red wires passed thru.


I took the dash off and ran the switch wires under the steering column mount.


Then came the hard part, getting the wires thru 2 sections of the bulkhead. I tried pushing one thru but it was too tight. So I figured I would push an ice pick thru and tape the wires to it and pull them thru. Well think again genocache, as the ice pick just pulled out of the tape. So I tried 1 wire at a time. NOT! Tape still pulled off.



Evidently all my ice picking widened the gap a little and I was finally able to just shove the wires thru 1 at a time.  :^)  Now the players were all on the same field!


New connectors were used, I used the Posi-tap connectors(blue).


I adjusted the switch so there is no pull when the pedal is up and it pulls out when the pedal moves.



Let there be light!


The engine bay wiring looks like;



After the bracket was cleaned up and painted the footwell looks like;


The spring is connected to the bottom of the pedal return spring. Here is the new switch in the closed position;



And open position;



Hoping this won't ever need to be redone in my lifetime.

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