Using an Aftermarket Brake Switch? Plunger Style?

[Big Dan]

I just finished swapping in a 96 XJ brake booster.  Like some on here, I didnt have brake lights after the swap.  I guess I ground too much material on the booster rod off.  Either way, I've tried spacers, adding more material, removing more material, etc etc and I can't get the flat spot just right to activate the brake switch.  

 

At this point I'm tired of messing with it.  Has anyone added a plunger style switch to their braking system?  If so, how did you do it?  In one thread, I saw where a guy had taken the bracket from a 95 XJ and wired in the 95 switch that way.  I am hoping there is another way to do it, besides that, so I don't have to go searching for brackets.

 

I'm open to any suggestions.

[Jeep Driver]

I'll be going to a Ford switch after I pull my column for this very reason. 

 

I intend to make new bracket.

[HOrnbrod]

8 hours ago, Big Dan said:

In one thread, I saw where a guy had taken the bracket from a 95 XJ and wired in the 95 switch that way.  I am hoping there is another way to do it, besides that, so I don't have to go searching for brackets.

 

Wouldn't be a very hard search; 91 and up MJ/XJ all use the same bracket and switch.

[ftpiercecracker1]

I did away with the original PITA brake switch a looooooong time ago.  Got a super generic GM plunger style switch, fab-ed up a plate with some sheet metal and slapped it in. Getting the plate oreinted right is by far the hardest part, but ero issues in as many years.

Sorry I don't have a p#, but here's a pic.

 

 

FPC.

 

 

 

Don't make it any more complicated than it needs to be. I bent a piece of sheet metal with my bare hands, cut it to size with a grinder, drilled 2 holes in it, one for the plunger and one for a bolt to hold it in place. 

 

Getting it positioned right is one of the hardest parts. You have to contort yourself to fit under the driver side dash and hold the plate in place and manipulate the brake pedal until you've got a good idea where it needs to go. Then you will most likely have to remove the pedal bracket assembly to drill the hole.

 

If I remember correctly, I opted to weld my plate in place. I did it without even removing the pedal bracket. I don't recommend doing this, but it's worked for me.

[ftpiercecracker1]

12 hours ago, HOrnbrod said:

 

Wouldn't be a very hard search; 91 and up MJ/XJ all use the same bracket and switch.

 

Is this bracket plug and play?

[HOrnbrod]

The mechanicals should be PnP, but I haven't personally done it. But electrically not; the switch won't plug into the Renix harness of course. There are three switches contained on the HO switch assembly; one for the brake lights, one for cruise, and one for the AW4 torque converter. You just need to ID with an ohmmeter and wire in the NO (normally open) switch for the brake lights. Easy peasy. 

[mjeff87]

Going off of memory, I want to say it's the pink and the white wire.

[HOrnbrod]

7 minutes ago, mjeff87 said:

Going off of memory, I want to say it's the pink and the white wire.

 

Just looked it up in the FSM - your memory is working well.  

[mjeff87]

LOL, I *had* a real nice picture of the one I scabbed into mine....before the photobucket debacle.  I deleted my whole account a little too quickly, LOL.

 

EDIT:  the bracket that holds the contact switch is welded to the updated pedal assembly.  It's not bolt-on, and you would either have to swap the entire assembly (which is what I did, and is easily one of the top 10 PITA things I ever did on my MJ......) or fab up a bracket of your own to hold the switch.  Once the switch is mounted, clip the wires to your old switch and splice them to the white and pink wires on the new switch.

 

 

[ftpiercecracker1]

8 hours ago, mjeff87 said:

LOL, I *had* a real nice picture of the one I scabbed into mine....before the photobucket debacle.  I deleted my whole account a little too quickly, LOL.

 

EDIT:  the bracket that holds the contact switch is welded to the updated pedal assembly.  It's not bolt-on, and you would either have to swap the entire assembly (which is what I did, and is easily one of the top 10 PITA things I ever did on my MJ......) or fab up a bracket of your own to hold the switch.  Once the switch is mounted, clip the wires to your old switch and splice them to the white and pink wires on the new switch.

 

 

 

 

Am i to understand the updated pedal assembly is not a direct bolt in?

[ftpiercecracker1]

21 hours ago, HOrnbrod said:

The mechanicals should be PnP, but I haven't personally done it. But electrically not; the switch won't plug into the Renix harness of course. There are three switches contained on the HO switch assembly; one for the brake lights, one for cruise, and one for the AW4 torque converter. You just need to ID with an ohmmeter and wire in the NO (normally open) switch for the brake lights. Easy peasy. 

 

 

I figured some splicing would be needed for the switch. Why is the TC wired through the brake pedal.  Lock up is overdrive and it only disengages when the brakes are applied?

[HOrnbrod]

40 minutes ago, ftpiercecracker1 said:

I figured some splicing would be needed for the switch. Why is the TC wired through the brake pedal.  Lock up is overdrive and it only disengages when the brakes are applied?

 

TC unlock occurs through a NC switch in the brake pedal switch assembly. When you touch the brakes it removes the 12V from solenoid #3 in the AW4 to disengage the TC. It can also be unlocked through solenoid #3 by signals from the TCM based on input from the from the speed sensor (VSS) and engine RPM.

[mjeff87]

The pedal assembly is 100% bolt in. The problem comes in with working on your head on the floorboard getting the old one out and the new one in.  It's not difficult per se, just a PITA maneuvering things around in a very tight, uncomfortable place.  At least it was for me, lol.

 

edit: rereading my post and I can see how confusing I worded it, sorry.  What I meant as the bracket that holds the plunger switch is not bolted to the pedal assembly, it's welded.  I thought I could just grab the bracket off a junkyard XJ/MJ and bolt it on to my old assembly...no dice.  That would have been too easy, and made perfect sense.  Too bad the engineers decided to weld it on instead of bolting it on :mad:

[Big Dan]

Alright so.. Maybe I could have had that flat spot on the push rod machined correctly. I say that because I wired in a plunger switch and still no brake lights.

Rear turning signals work fine as do the rear lights.. Just no brake lights.

To ensure the switch wasn't bad, I connected the brake switch wires together (as it's just an open/close) and still no luck.

Any ideas as to a fix? I did have functioning brake lights before.

Sent from my Nexus 6P using Tapatalk

[HOrnbrod]

Sounds like you are missing the constant 12V at the brake switch feed wire. Looks like #6 on the Renix fuse block.

[Big Dan]

And, as usual, you would be correct. I thought the fuse was good... And it was not. You saying that made me check it again.

Brake lights work. Thanks.

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[Big Dan]

On 12/11/2017 at 11:32 AM, mjeff87 said:

It's not bolt-on, and you would either have to swap the entire assembly

 

 

Something that some folks could consider is cutting the weld off of the donor assembly's bracket.  The brake assembly and the switch bracket have holes drilled, in both of them, that line up perfectly.  You could then bolt up the bracket to your truck's assembly, using those pre-drilled holes.