[BigMac4840]

I have a 2017 Armada that wouldn't start one day. The screen kept prompting me to press the brake even though the brake was pressed. I removed the switch on the brake pedal, took it apart, cleaned the contacts and reinstalled it. After that, it worked fine, but I went ahead and ordered a replacement switch (Amazon.com: IDIYA New Auto 2 Pins Brake Clutch Pedal Cruise Control Release Stop Light Switch OEM 25300-AT300 25300AT300 (1 Pack) : Automotive) just in case it acted up again. Everything worked fine for several months, but eventually the problem came back so I went ahead and replaced the switch. The new switch worked for a few starts, but then stopped again. If I fiddle with it for a while, it eventually works, but then a few starts later, it stops working again. If I remove the switch entirely, it doesn't start, but if I jump the connection with a small wire it works fine. Everything seems to work normally with the connection permanently jumped, so I'm not sure what purpose this switch is serving. Can I just leave this connector jumped, or am I totally missing something?

 

[amc49]

Read your part description in red above CLOSE. Make SURE car in cruise DOES switch it off when the brake pedal is pushed or the car will not cut off cruise which can lead to an accident.

The brake pedal MUST cancel cruise or you are asking for it.

Also check somewhere with some room in front of car whether the car will start while trans not in neutral, which can make car take off.

 

[BigMac4840]

Read your part description in red above CLOSE. Make SURE car in cruise DOES switch it off when the brake pedal is pushed or the car will not cut off cruise which can lead to an accident.

The brake pedal MUST cancel cruise or you are asking for it.

Also check somewhere with some room in front of car whether the car will start while trans not in neutral, which can make car take off.

I can confirm that cruise control still gets canceled when the brake is depressed. I also tried starting the car while it's in in drive this morning as you suggested. I'd never tried that before, but it just beeps at me and doesn't start, which I think is probably expected behavior. For the life of me, I just can't find any downside to not having this switch, which doesn't make any sense to me.

 

[amc49]

Those would be the big ones that come to mind instantly. Can't say what else without a schematic but there would be something like signal to BCM to enable starting in some more complex a way.

 

[BigMac4840]

UPDATE: Everything worked fine for about a week, but suddenly the cruise control stopped working. The light would just flash when you try to turn it on. I'm guessing the computer went through enough drive cycles without seeing a change on that input and finally went into an error state. I reconnected the switch and everything went back to working normally. I guess we'll see how long it lasts.