The Ford Barn

Flathill · 01-04-2016, 07:52 AM

I have a new brake switch for a 36 ford with mechanical brakes.
Is the switch set up with normally open or closed contacts before moving its stem (rod) in ?
I tested the switch with a ohm meter with connections at the 2 wire terminals and without moving the switch stem the contacts appear to be closed showing a closed circuit. As I move the stem in a good ways it shows a open contact.
This seems to be the opposite of how I think it should work ?
I would think pushing the brake switch stem plunger in by stepping on the brake pedal would close the circuit and the brake tail light would come on.
Haven't installed the switch as I would like to be sure it functions properly on the work test bench first.

flatheadmurre · 01-04-2016, 08:01 AM

Nothing strange about that the plunger is depressed from the break pedal in resting position and as soon as you set the foot on the pedal the lights go on.

Flathill · 01-04-2016, 08:17 AM

OK-With the brake pedal in the resting position the brake switch plunger is pushed in opening the circuit.
When applying the brake pedal the plunger is moved with it's own spring action back to it's closed position.
So a new brake switch will be in a closed circuit position when not installed.
I think the one I have is OK to install.

JM 35 Sedan · 01-04-2016, 09:18 AM

Go under your '36 and look at the old/existing brake light switch that's fastened to the brake/clutch pedal assembly frame. (assuming there is an existing switch

) and see where and how the old one is mounted/connected, etc.

With the E brake engaged/wheels chocked, have someone sit in drivers seat and push the brake pedal in and out a few times, while you watch from below to see how the switch works mechanically and also how the two electrical wires are routed and connected.

When you put the new switch in place, and attach the two little terminated leads, hopefully with insulated barrel crimps on terminals, you will have a slight adjustment (for and aft, via elongated mounting holes) on the position of the switch that must be made to tune in when the switch contacts make/break to turn the brake light(s) on and off. Patience and time are your friends here in getting this brake light switch tuned in correctly.

Flathill · 01-04-2016, 05:51 PM

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Thanks for the replies. I think the new brake switch is OK. I will have to put on the old cloths and climb under the 36 ford and have a look to see how the brake switch works mechanically and is wired.

01-04-2016, 07:52 AM	#1
Flathill Member Join Date: Mar 2012 Location: Grantham, NH Posts: 49	Brake Switch Mechanical Brakes I have a new brake switch for a 36 ford with mechanical brakes. Is the switch set up with normally open or closed contacts before moving its stem (rod) in ? I tested the switch with a ohm meter with connections at the 2 wire terminals and without moving the switch stem the contacts appear to be closed showing a closed circuit. As I move the stem in a good ways it shows a open contact. This seems to be the opposite of how I think it should work ? I would think pushing the brake switch stem plunger in by stepping on the brake pedal would close the circuit and the brake tail light would come on. Haven't installed the switch as I would like to be sure it functions properly on the work test bench first.

01-04-2016, 08:01 AM	#2
flatheadmurre Senior Member Join Date: Apr 2015 Location: Sweden Posts: 3,045	Re: Brake Switch Mechanical Brakes Nothing strange about that the plunger is depressed from the break pedal in resting position and as soon as you set the foot on the pedal the lights go on.

01-04-2016, 08:17 AM	#3
Flathill Member Join Date: Mar 2012 Location: Grantham, NH Posts: 49	Re: Brake Switch Mechanical Brakes OK-With the brake pedal in the resting position the brake switch plunger is pushed in opening the circuit. When applying the brake pedal the plunger is moved with it's own spring action back to it's closed position. So a new brake switch will be in a closed circuit position when not installed. I think the one I have is OK to install.

01-04-2016, 09:18 AM	#4
JM 35 Sedan Senior Member Join Date: May 2010 Location: Near Rising Sun, Maryland Posts: 10,859	Re: Brake Switch Mechanical Brakes Go under your '36 and look at the old/existing brake light switch that's fastened to the brake/clutch pedal assembly frame. (assuming there is an existing switch ) and see where and how the old one is mounted/connected, etc. With the E brake engaged/wheels chocked, have someone sit in drivers seat and push the brake pedal in and out a few times, while you watch from below to see how the switch works mechanically and also how the two electrical wires are routed and connected. When you put the new switch in place, and attach the two little terminated leads, hopefully with insulated barrel crimps on terminals, you will have a slight adjustment (for and aft, via elongated mounting holes) on the position of the switch that must be made to tune in when the switch contacts make/break to turn the brake light(s) on and off. Patience and time are your friends here in getting this brake light switch tuned in correctly. __________________ *John* *"Never give up on what you really want to do. The person with big dreams is more powerful than one with all the facts". Albert Einstein*

01-04-2016, 05:51 PM	#5
Flathill Member Join Date: Mar 2012 Location: Grantham, NH Posts: 49	Re: Brake Switch Mechanical Brakes Sponsored Links (Register now to hide all advertisements) Thanks for the replies. I think the new brake switch is OK. I will have to put on the old cloths and climb under the 36 ford and have a look to see how the brake switch works mechanically and is wired.