LS Swap '04 Jeep - Brake switch wiring help

[Mufasa_swap]

I did a LS GenIII swap and needing help with wiring in Pin33 Purple TCC Brake Switch/Cruise Control Release Switch Signal wire. Question: is there a way that I can use the original '04 Jeep brake switch and splice in the Purple TCC wire?? Or do I need to use the recommended Brake Switch (Model#: SLS179) for a late '90's model Camaro in order to wire in the TCC wire. Looking for help. Thanks in advance!

 

[Greg]

Are you using a kit for the swap?

I'd just swap in the Camaro brake switch, there must be a reason they'd recommend it.

You could call Motec in Vegas and see what they recommend. - https://lswrangler.com/index.html

 

[Mufasa_swap]

Are you using a kit for the swap?

I'd just swap in the Camaro brake switch, there must be a reason they'd recommend it.

You could call Motec in Vegas and see what they recommend. - https://lswrangler.com/index.html

Not using a kit. We built the wire harness ourselves. The person that was helping me is no longer available. I have it wired in but get no power to the tail lights. This is how I currently have it wired. Using a test light everything is working except for the taillights and i dont know why

 

[DaveB]

These switches have two types of contacts in them, normally closed and normally open. The brake lights hook to the normally open switch so that when brakes are applied the lights come on. The TCC is on the normally closed position which feeds 12 V to the torque converter lock up solenoid. When you apply the brakes the TCC solenoid is disconnected from power so that the torque converter wont fight the brakes. The ground side of the solenoid is driven by the ECM which pulls it low to lock up the TCC. I would check to see that you have it hooked up properly and that the push button is moving properly with the brake pedal in both the on and off positions.

 

[Mufasa_swap]

These switches have two types of contacts in them, normally closed and normally open. The brake lights hook to the normally open switch so that when brakes are applied the lights come on. The TCC is on the normally closed position which feeds 12 V to the torque converter lock up solenoid. When you apply the brakes the TCC solenoid is disconnected from power so that the torque converter wont fight the brakes. The ground side of the solenoid is driven by the ECM which pulls it low to lock up the TCC. I would check to see that you have it hooked up properly and that the push button is moving properly with the brake pedal in both the on and off positions.

DaveB - I appreciate the feedback and detailed operation. I had an idea of how it worked but your description made it clear. I tested the open and closed positions with a test light. I updated the previous posted sketch and added labels. The way I currently have it wired is:
1 = TCC (Purple wire / Pin33)
2 = 12V+ (constant positive)
3 = Keyed switch (12+ when ignition is on)
4 = Brake lights

KEY ON
With the switch pressed in (Brake off) - 1 (TCC) shows closed circuit
With the switch out/released (Brake on) - 4 (brake lights) are closed circuit
Everything seems to be working right however, my brake lights on the jeep don't come on when the pedal is pressed (switch button out), but the switch is working properly?

 

[glockman]

Do you have a good ground that ties tcc to ground when the brake is press and also provides a ground for the 12+ to the lights when the brake pedal is depressed?

 

[Mufasa_swap]

Do you have a good ground that ties tcc to ground when the brake is press and also provides a ground for the 12+ to the lights when the brake pedal is depressed?

That I'm not sure. I know I dont have a ground on the switch. Since the TCC (purple wire) is coming for the PCM (pin33) I would think that should already be grounded. I could be wrong though.

 

[glockman]

90% of electrical issues on vehicles I've found to be bad grounds. Make sure that TCC goes to ground when the brake is pressed. My next move would be provide a ground at the brake light and see if you have 12v at the light itself.

 

[Mufasa_swap]

90% of electrical issues on vehicles I've found to be bad grounds. Make sure that TCC goes to ground when the brake is pressed. My next move would be provide a ground at the brake light and see if you have 12v at the light itself.

The original brake switch shows a ground wire and the new switch doesnt. Could this be my issue and that I need to tie that wire to a ground?

 

[glockman]

Could be. The brake lights are grounded at the light on my 06 if I remember right. I'd pull the light and check that it has a constant ground, the 12v is switched. However, you will need the ground for the TCC.

 

[Mufasa_swap]

So I found a fix for my issue. I appreciate ALL the help and suggestions. I ended up using a relay and tapping it into my original brake switch and the ECM. I also want to give a HUGE shout out to my friend Greg B and Charlie G for all the time and brain work that went into the swap.