Stoplight Switch to Brake Pedal Linkage

My brake lights are not working I believe because of the poor linkage between the stoplight switch and the brake pedal. When I push the stoplight switch forward manually, the brake lights do go on. I tried adjusting the switch on the mount and it still won't move with the brake pedal. Do I need to adjust the brake pedal travel? Anything else I can try? Thank you all.

My experience was that the contacts are burnt right where the "sweet spot" is for making connection at the right amount of pedal travel.

I pried one apart and tried to refurbish it but it was too damaged to get the sweet spot working.

I ended up buying a new one.

That link fell off on mine seems common, I just put it back on but haven't checked it in a while

I put three nylon washers between the switch and the switch mount on the front bolt closer to the firewall. This allows for better adjustment and seems to be working well.

The swich fails often...just replace it

Its was not the switch - it was and is the design of the mount and arm. Many replace the switch only to have the same problem with a new switch.

I'm having the same problem your having. Did you ever find a solution for it?

Replacing the switch will likely not fix the problem. To increase the travel of the switch, I put 3-4 washers between the switch and the switch mounting plate on the front screw of the mount only. You can loosen the rear screw to make it easier. You might need fewer or more washers. You will need to experiment to see how many washer you need. You are trying to move the starting position of the switch very slightly farther away from the firewall. I also tightened up the linkage between the switch and brake pedal with some slight bending and by replacing the outside washers that hold the linkage both on the brake pedal and brake light switch. I put thin black rubber tubing over one end of the linkage tip and a tighter fitting lock washer on the over end - this holds the linkage in place as tightly as possible.

P.S. This took me many hours of trial and error but has now proved reliable for several months. Let me know if you need any additional info. I can post some pics if you need. Thanks for the question.

I replaced that goofy switch with a cheap one from a jeep. Made a bracket out of angle iron and its been fine going on a few years now.

great

I went even further with my new switch. I picked a waterproofed, normally closed switch and mounted it so that as soon as the brake pedal lever comes off the stop it turns the brake lights on. No free travel adjustment necessary. The AMG garbage design of a switch with zero free travel adjustment testifies to their engineering. The fact that they used the same switch used in the M151 and other vehicles was a good idea but the implementation was atrocious!

After you correct their design foopah install some LED bulbs in the lamps to minimize the current draw with the lights on to prolong the life of your new switch.

B7152 Normally Closed, High Pushbutton, Low Force | CPI

CPI's Line of Sealed Pendant Switches achieve reliable momentary contact under the wettest, and harshest environmental conditions.

www.cpi-nj.com

papakb said:

I went even further with my new switch. I picked a waterproofed, normally closed switch and mounted it so that as soon as the brake pedal lever comes off the stop it turns the brake lights on. No free travel adjustment necessary. The AMG garbage design of a switch with zero free travel adjustment testifies to their engineering. The fact that they used the same switch used in the M151 and other vehicles was a good idea but the implementation was atrocious!

After you correct their design foopah install some LED bulbs in the lamps to minimize the current draw with the lights on to prolong the life of your new switch.

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Whats the brand/part number of the new switch you used to replace the older AMG switch?

The trucks with over drive { 4L80E } have a dual switch...one for brakes, one for torque converter connected together,
Also....there are two different brands of the single switch...one you can open it up.

86humv said:

The trucks with over drive { 4L80E } have a dual switch...one for brakes, one for torque converter connected together,
Also....there are two different brands of the single switch...one you can open it up.

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Hate to bring back a zombie thread but I wanted to ask is it possible to just replace the brake side of the dual switch? The torque converter side of mine seems to work fine (assuming it is normally closed and opens when you push the pedal while the brake side is normally open?). It is about half as much $ to order just the brake side so if it's possible to just swap that one switch out instead of the whole assembly, that would be great. Looking at it, I don't see why it wouldn't be possible but maybe I am missing something. Thanks!

diesel_dave said:

Hate to bring back a zombie thread but I wanted to ask is it possible to just replace the brake side of the dual switch? The torque converter side of mine seems to work fine (assuming it is normally closed and opens when you push the pedal while the brake side is normally open?). It is about half as much $ to order just the brake side so if it's possible to just swap that one switch out instead of the whole assembly, that would be great. Looking at it, I don't see why it wouldn't be possible but maybe I am missing something. Thanks!

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Yes you can replace just the brake side using the single switch. Look at pictures of both and you'll see they are just bolted together.

springer1981 said:

Yes you can replace just the brake side using the single switch. Look at pictures of both and you'll see they are just bolted together.

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Awesome! Just what I was looking for. After looking at a bunch of pics it seemed like it should be very straightforward but it wouldn't be the first thing I thought was straightforward only to find out halfway through there is some kinda hidden gotcha. I'll order just the brake side from Mac Motors then. Thanks for saving me about $50.

diesel_dave said:

Awesome! Just what I was looking for. After looking at a bunch of pics it seemed like it should be very straightforward but it wouldn't be the first thing I thought was straightforward only to find out halfway through there is some kinda hidden gotcha. I'll order just the brake side from Mac Motors then. Thanks for saving me about $50.

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There are different kinds i think, make sure the one you get looks like what you have on yours.