Brake Pedal Switch & PCM Questions
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Professional
Joined: Nov 2006
Posts: 135
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From: Arizona
Brake Pedal Switch & PCM Questions
Question 1:
I went through a real long saga with a dealership and in the end, I wound up with a reconditioned PCM. In any event, I rarely drive the vehicle here (golf cart friendly town), but since that PCM change, I seem to be blowing switches and relays when I do drive it. First the heater blower, then the ABS speed sensor on the differential, now the brake light switch on the pedal. When the guy wired the new PCM, he hot wired one wire to the transmission, which freaked me out because it was just dangling and one of the connectors obviously got cracked while putting it on. Took it back to this dealership and they just put electrical tape around things. At that point, I just walked away from them, never to return (I pray). Could it be that this PCM could be blowing the relays/sensors?
Question 2:
Now, to the brake switch problem. Lights are staying on. Happened a couple of weeks ago, and again last night, then went off after playing with pedal a little. Then, they went back on last night and had to pull the negative battery cable to stop. So, I will be changing out the brake switch tomorrow. I found this set of instructions on the web and just want to know if this is it, including adjustment:
To remove old:
1. Remove lower steering column cover and knee blocker panel from instrument panel.
2. With the brake pedal fully pressed, rotate the stop lamp switch counter clockwise until you feel it unlock from its previous location, then pull it towards you. (get friend to help with pedal)
3. Disconnect wire connector from stop lamp switch by depressing the lock tabs holding stop lamp switch to mounting bracket and remove switch.
To install new:
1. Connect the harness connector to the stop lamp switch.
2. While pressing the brake pedal, insert switch into the keyed hole in the bracket and rotate the switch into the locked position.
3. Gently pull back on the brake pedal until the pedal will go no further. This will cause the switch plunger to ratchet backward to the correct position. No further adjustment is necessary.
I went through a real long saga with a dealership and in the end, I wound up with a reconditioned PCM. In any event, I rarely drive the vehicle here (golf cart friendly town), but since that PCM change, I seem to be blowing switches and relays when I do drive it. First the heater blower, then the ABS speed sensor on the differential, now the brake light switch on the pedal. When the guy wired the new PCM, he hot wired one wire to the transmission, which freaked me out because it was just dangling and one of the connectors obviously got cracked while putting it on. Took it back to this dealership and they just put electrical tape around things. At that point, I just walked away from them, never to return (I pray). Could it be that this PCM could be blowing the relays/sensors?
Question 2:
Now, to the brake switch problem. Lights are staying on. Happened a couple of weeks ago, and again last night, then went off after playing with pedal a little. Then, they went back on last night and had to pull the negative battery cable to stop. So, I will be changing out the brake switch tomorrow. I found this set of instructions on the web and just want to know if this is it, including adjustment:
To remove old:
1. Remove lower steering column cover and knee blocker panel from instrument panel.
2. With the brake pedal fully pressed, rotate the stop lamp switch counter clockwise until you feel it unlock from its previous location, then pull it towards you. (get friend to help with pedal)
3. Disconnect wire connector from stop lamp switch by depressing the lock tabs holding stop lamp switch to mounting bracket and remove switch.
To install new:
1. Connect the harness connector to the stop lamp switch.
2. While pressing the brake pedal, insert switch into the keyed hole in the bracket and rotate the switch into the locked position.
3. Gently pull back on the brake pedal until the pedal will go no further. This will cause the switch plunger to ratchet backward to the correct position. No further adjustment is necessary.
Legend
Joined: Jul 2011
Posts: 8,259
Likes: 4
From: Austin, TX
The hot wiring of one of the wires is not the correct way of doing this. I would take it back to them and make them fix it. Ask for a different mechanic. Only talk to service manager. I would also contact Dodge Customer Service. They will have a problem with a dealer doing this as well.
The alteration of the wiring could indeed have an effect. Some components require something like 5v, and to hit it with 12v would be problematic and could casue significant problems.
I w ould een hold on on the brake switch issue as well. It could be related. The PCM typically functions by closing the ground side of circuits, and the brake switch is monitored by the PCM.
The alteration of the wiring could indeed have an effect. Some components require something like 5v, and to hit it with 12v would be problematic and could casue significant problems.
I w ould een hold on on the brake switch issue as well. It could be related. The PCM typically functions by closing the ground side of circuits, and the brake switch is monitored by the PCM.
All Star
Joined: Sep 2012
Posts: 803
Likes: 87
From: Europe
I found this set of instructions on the web and just want to know if this is it, including adjustment:
To remove old:
1. Remove lower steering column cover and knee blocker panel from instrument panel.
2. With the brake pedal fully pressed, rotate the stop lamp switch counter clockwise until you feel it unlock from its previous location, then pull it towards you. (get friend to help with pedal)
3. Disconnect wire connector from stop lamp switch by depressing the lock tabs holding stop lamp switch to mounting bracket and remove switch.
To install new:
1. Connect the harness connector to the stop lamp switch.
2. While pressing the brake pedal, insert switch into the keyed hole in the bracket and rotate the switch into the locked position.
3. Gently pull back on the brake pedal until the pedal will go no further. This will cause the switch plunger to ratchet backward to the correct position. No further adjustment is necessary.
To remove old:
1. Remove lower steering column cover and knee blocker panel from instrument panel.
2. With the brake pedal fully pressed, rotate the stop lamp switch counter clockwise until you feel it unlock from its previous location, then pull it towards you. (get friend to help with pedal)
3. Disconnect wire connector from stop lamp switch by depressing the lock tabs holding stop lamp switch to mounting bracket and remove switch.
To install new:
1. Connect the harness connector to the stop lamp switch.
2. While pressing the brake pedal, insert switch into the keyed hole in the bracket and rotate the switch into the locked position.
3. Gently pull back on the brake pedal until the pedal will go no further. This will cause the switch plunger to ratchet backward to the correct position. No further adjustment is necessary.
Brake switch has three separate contactors, one open and two closed; first set is for brake lights (which is wired to battery and does nothing to PCM), second set is brake sense for PCM (ground, and when pedal is pressed these contactors open), third set is for cruise control and like the second this cuts ground.