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Can a broken brake light switch....

2297 Views 3 Replies 3 Participants Last post by  ExplorerPIU2013
.... cause the car not to start???

Hi there, new to the forum. Not an expert on electrical guys, here's the story:

I have a 2002 Ford Explorer Sport. My wife wanted to start it yesterday to no avail. It made a rapid clicking noise underneath the dash in the brake pedal area. So I thought: OK, must be a switch or relay. The engine did not crank at all. Here's the quick version:

- turning the ignition, key in position 1: at first it did the normal safety belt "ring" a little faint though, clicking noise from the brake pedal area, dash lights were on
- turning the ignition, key in position 2: no starter activity, no engine cranking, clicking noise from the brake pedal area, dash lights were on
- key in position 0/no key: the clicking noise was still there....clicking away
- unhooked the battery to save it
- checked all fuses (under the hood and interior fuse box left dash): OK
- did some research on forums => looks like the brake light switch is broken. Easy $15 part.
- Got a new brake light switch from autozone
- Installed the new switch, turned the key, one louder click => nothing worked at all, no dash lights, no starter activity, no cranking. Seemed like a completely dead battery or a blown fuse.
- Checked battery voltage (it's rather new anyway). Battery is fine.
- Checked all fuses again, all fine
- Though the new switch might be faulty, switched back to the old one. Turn the key, car starts, all perfectly fine. Hhmmmmm......

So with that I thought: no blown fuses, old switch might not be perfect b/c old, battery works fine. Must be something with the wiring. A short, loose plug/switch.

I just do not understand the cause/effect of brake light switch <=> engine not starting/cranking.

- Thought the new switch would be better than the old one and wanted to test it again. Installed new switch => car starts, all fine.

- Then my wife drove the Explorer to the store, got back to the car. Car wouldn't start.

- I drive to the store, unhook the battery, mess around with the switch (basically just taking it off of the pedal) Start the car. All fine.

- This morning I went outside if there are any issues with the tail lights. The car stared w/o any problems. All tail lights/signals work properly.

So I tried to diagnose as much as possible. As I said, not an expert on wiring/electrical, but since there is an issue to get the car running as well I think there must be a loose switch or plug, or a broken wire. Is the wiring harness that carries the brake light switch also responsible or the ignition?

Any help would be awesome guys. Another thing, I bought the car used in 2007, except from a new ignition coil I didn't have any serious issues with the car. I replaced the multi-function switch (turn signals, whiper etc.) in 2009 or so.

Thank you!!!
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I see this post is 4 years old!!I have 2002 Ford Explorer Sport Purchased used Aug 2017. Vehicle sat for a year outside in Az bad engine. I had engine rebuilt and have put 25k on it. In the last month I have developed (2) electrical issues. (1) when I drive over rough road the engine stalls. It will start back up immediately EVERY time. (2) My left Brake light Turn signal does not work at all. I swapped sockets and bulbs from Rt side. Not bulbs or sockets. Did you solve your problem? Maybe my Bk light switch is bad? Thank you Don K7LHR
2002 ford explorer sport intermittent electrical problem

!I have 2002 Ford Explorer Sport Purchased used Aug 2017. Vehicle sat for a year outside in Az bad engine. I had engine rebuilt and have put 25k on it. No problems until last month. In the last month I have developed (2) electrical issues. (1) when I drive over rough road the engine stalls. It will start back up immediately EVERY time. (2) My left rear Brake light Turn signal does not work at all. I swapped sockets and bulbs from Rt side. Not bulbs or sockets. There is and old post from 2014 about bk light switch effecting starting engine. Maybe my Bk light switch is bad? Can anyone HELP me? Thank you Don K7LHR
I would be apt to think the ignition master switch itself has an intermittent connection
problem inside the switch itself.

Taking the electrical switch portion out out the steering column and spraying the switch
out with CRC electrical contact cleaner may be a solution rather than purchasing another
switch.

I had to replace this on my wife's 2002 Mazda Tribute, spraying didn't fix it and Rockauto
had a Standard Brand replacement for around $12 shipped using their discount code.

Hope this probable solution helps.
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