I Installed a wj booster master and I can't get the brake lights to come on. I drilled the hole out to 5/8 and shaved the back flat like the other threads have shown. Most of the time it seems that people have problems with the lights staying on but mine won't light up at all. I thought shaved too much off the end at first so I welded the meat back on and checked the clearance between the switch and stock brake rod. Then I re shaved the wj brake rod to match. I'm pretty sure that I re attached the switch the correct way since it seems like there is only one way to put it on. I pushed on the switch with a screwdriver and the lights work but when I push the pedal nothing. Any ideas that might help me. I'm completely stumped.
-
Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.
Brake light switch?
- Thread starter bails85
- Start date
Ok I did a lot of searching and I think I found the answer. Is there a way to get to the switch without playing contortionist upside down? Can I remover some of the dash pieces to get to it easier? I'm a pretty big guy and I don't really fit under the dash to well.
ParadiseXJ
NAXJA Forum User
- Location
- Paradise, CA 95969
You can remove the lower dash by removing 4-5 screws at the "seam". It won't make a huge difference but it DOES make a bit more accessible.
I found one of the wires broken at the plug itself.
I found one of the wires broken at the plug itself.
bigalpha
Moderator
- Location
- Tucson, AZ
I had to adjust the tightness of the bolt running through the sensor and the pedal assy to get my lights working correctly.
Make sure you adjust the white sensor further up on the assy. If you don't, it'll affect your torque converter lock up.
Make sure you adjust the white sensor further up on the assy. If you don't, it'll affect your torque converter lock up.
bigalpha
Moderator
- Location
- Tucson, AZ
The brake light switch you're fighting with right now is only for the brake lights. You can see it in the below picture in the foreground. The brake light switch is black, with a brown electrical connector.
The cruise control vacuum dump (and TC lock up sensor) is the big white sensor in the back ground.
The bottom of the picture is pointing forward to the firewall, and the top of the picture pointing to the driver seat (click for giant size).
The idea here is that there is a plunger that sticks out of the white sensor towards the brake pedal assembly. You can barely see it in my picture. As you press the brake pedal, that plunger will extend. This controls TC lock up - at least it does in my MJ.
You can verify functionality by removing it and clipping a DMM to each of the terminals on the sensor and measuring for resistance as you depress the plunger. I don't recall which way the contacts are closed (I think it's when the plunger is all the way out). The recommended action is to go ahead and pop it apart and clean it up while you have it out; this sensor can get dirty/gunky sometimes anyways.
The white sensor has a plug with two wires, a black wire and a blue wire with an orange tracer. I assume the black wire is going to be a ground; someone will have to double check in an FSM.
Anyways, make sure that the plunger extends fully when the brake pedal is depressed and make sure it is fully unextended with the brake pedal in the normal height. You will have to do this with the truck running.
To check for TC lock up, you will tap the brake pedal while you are cruising at a constant speed (above 50mph, IIRC). You will notice a ~300 RPM spike and you should be able to hear the engine rev up a bit. With the TC never locked up, your trans will run hotter than normal; this is what was wrong with mine.
All of that being said, you may not have to adjust that white sensor. Just make sure it's working. Also, tighten the bolt that runs through your brake pedal sensor some more - I had to fidget with mine for a while to get the lights working correctly.
The cruise control vacuum dump (and TC lock up sensor) is the big white sensor in the back ground.
The bottom of the picture is pointing forward to the firewall, and the top of the picture pointing to the driver seat (click for giant size).
The idea here is that there is a plunger that sticks out of the white sensor towards the brake pedal assembly. You can barely see it in my picture. As you press the brake pedal, that plunger will extend. This controls TC lock up - at least it does in my MJ.
You can verify functionality by removing it and clipping a DMM to each of the terminals on the sensor and measuring for resistance as you depress the plunger. I don't recall which way the contacts are closed (I think it's when the plunger is all the way out). The recommended action is to go ahead and pop it apart and clean it up while you have it out; this sensor can get dirty/gunky sometimes anyways.
The white sensor has a plug with two wires, a black wire and a blue wire with an orange tracer. I assume the black wire is going to be a ground; someone will have to double check in an FSM.
Anyways, make sure that the plunger extends fully when the brake pedal is depressed and make sure it is fully unextended with the brake pedal in the normal height. You will have to do this with the truck running.
To check for TC lock up, you will tap the brake pedal while you are cruising at a constant speed (above 50mph, IIRC). You will notice a ~300 RPM spike and you should be able to hear the engine rev up a bit. With the TC never locked up, your trans will run hotter than normal; this is what was wrong with mine.
All of that being said, you may not have to adjust that white sensor. Just make sure it's working. Also, tighten the bolt that runs through your brake pedal sensor some more - I had to fidget with mine for a while to get the lights working correctly.
Can anyone help tracking down the white switch above? I need a plunger style switch with the wiring for a brake light. I've found a bunch of plunger style brake light switches, but they all have a way smaller diameter than the cruise control vacuum switch. All of the jeep part numbers I have either lead to the SL S66, which is a smaller diameter, or they are the cam style sensors like the factory used that won't work with the master cylinder I've got now.
Thanks if anyone can help out with this.
Thanks if anyone can help out with this.
