Engine will not turn over sometimes?

2002 MERCURY MOUNTAINEER
200,000 MILES • 4.0L • 4 CYL • 4WD • AUTOMATIC
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LUIS15
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Car won’t turn over sometimes, it just has the dash lights on and everything else on, but it won’t start/crank. I replaced the starter last year and the battery I just replaced a day ago and I replaced the starter relay and the battery terminals. It would sometimes crank and there would be times it wouldn’t crank no matter how much I turn the key, it would crank after waiting a few minutes sometimes. I been trying to figure out the problem, but I can’t seem to find it.
Dec 30, 2022 at 5:55 PM
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STRAILER
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It sounds like the starter motor has gone bad again, but to be sure use a test light on the starter trigger wire when the key is in the crank position. If it lights up the starter is bad.

This guide can help you confirm the failure:

https://www.2carpros.com/articles/starter-not-working-repair

Here is how to change out the starter motor in the images below. Please let us know what happens.
Dec 31, 2022 at 11:51 AM
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LUIS15
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I suspected it was the starter bad. I tapped it one time when it turned off on me and it turned on, but I was hoping it wasn’t the starter because that means it only lasted me a year.
Dec 31, 2022 at 12:08 PM
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STRAILER
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yep, it should be under warranty, I would go with a name brand rebuild if they dont give you another one.
Dec 31, 2022 at 5:11 PM
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LUIS15
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Thank you.
Jan 1, 2023 at 6:48 AM
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STRAILER
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Use 2CarPros anytime, we are here to help. Please tell a friend.
Jan 2, 2023 at 1:26 PM
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LUIS15
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Update: I replaced the starter and I still get the same issue, but I noticed something when it doesn’t want to start i turn the key and nothing but when I press on the brake and turn the key it starts but I never had to do that before ever. any advice?
Feb 3, 2023 at 10:50 AM
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STRAILER
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That is a safety procedure most cars have. The starter relay is controlled by the PCM which has a brake light switch input, here is the starter system wiring diagrams so you can see how it works, also please check fuse # 23 and 12 in the fuse panel under the hood, and fuse # 29 in the interior fuse panel.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Check out the images (below). Please let us know what happens.
Feb 3, 2023 at 1:44 PM
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LUIS15
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Okay, thank you. I will check those. I just find it weird that I didn’t start getting the issue of starting the car until wintertime. I've never had that issue before that, but I will check the fuses noted.
Feb 3, 2023 at 3:57 PM
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LUIS15
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I checked the fuses all are good not blown, I feel like the anti-theft system is triggering due to freezing temperatures triggering a no start unless I press the brake and turn the key as the problem only started when it got really cold is it possible? I’ve changed almost everything except ignition switch which I have, but haven’t changed yet because I’m afraid it won’t solve the issue.
Feb 4, 2023 at 8:54 AM
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STRAILER
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So, does it start with your foot on the brake still? Let's run the codes to see if the security system is having an issue. You can get a CAN scanner (Controller Area Network) from Amazon.

Here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

and

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Here is a list of CAN scanners starting at about $25.00 on Amazon:

https://amzn.to/3DBMlc7

Let me know please.
Feb 4, 2023 at 12:42 PM
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LUIS15
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I have a CAN scanner and I have no codes or any problems that are coming up. So, when I start the car sometimes it would start other times it won’t, dash lights are on and I changed the battery the starter and the battery terminals all brand new and still same problem, fuses are good. I have the ignition switch and a brand-new key switch on standby. I haven’t changed those yet as I'm afraid it won’t solve the problem. So it will only start back up when I have the foot on the brake and turn the key then it would turn over and start like normal but then there’s times where I don’t need to press on the brake and it just starts when I just turn the key I only press on the brake when it doesn’t want to turn over the engine. Could it be my anti-theft system is like triggering the no start? Cause I read somewhere that some anti-theft system when they lock up you have to press on the brake. I’m running out of ideas.
Feb 4, 2023 at 9:08 PM
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STRAILER
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Let's confirm whether the start trigger wire is getting power or not getting power when in the crank position.

This guide will help:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Please let us know what you find.
Feb 5, 2023 at 1:33 PM
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LUIS15
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Yeah, wires seem to get power no issue with wires. A faulty key switch or a faulty ignition switch wouldn’t cause that kind of problem where it would only start if I press on the brake, right?
Feb 5, 2023 at 2:19 PM
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STRAILER
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If the trigger wire is getting power (12 volts) and the positive battery cable is in good shape with good connections, then the starter motor is no good.
Feb 6, 2023 at 12:48 PM
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LUIS15
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The issue is I just replaced the starter motor. The first time I replaced it is one year ago and the second time I replaced it a week ago and the same problem persists. Does the ignition switch and key ignition rule out then?
Feb 6, 2023 at 1:48 PM
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STRAILER
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Does the test light work when testing the trigger wire? Nice and bright? is so the starter is bad, or the positive battery cable needs replacement, if you turn the key to crank and the power goes out at the starter the cable is bad. Can I ask which brand starter motor you are using, some rebuilds are just painted used parts.
Feb 7, 2023 at 12:00 PM
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LUIS15
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Duralast its new not remanufactured. I replaced the starter, battery, battery terminals. When I turn to crank the car, all lights turn on including headlights, but engine doesn’t turn. It turns when I press on the brakes to start the vehicle. And I checked the fuses, and I tested the wires with the cables, and everything seemed normal. I think I’m going to have to check the wires when the car doesn’t want to turn over, but I have to wait for that to happen. I feel like it has to be some sort of electrical issue with the wires or a short maybe. I haven’t changed the ignition switch and cylinder, yet I have those parts ready but if it was the ignition switch, I feel like it wouldn’t have started when I press on the brakes.
Feb 7, 2023 at 3:37 PM
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STRAILER
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The PCM controls when the engine can crank over which could be bad, as you can see by the starter circuit wiring diagrams. Other than that, I would check the wiring and then replace the PCM. Can i ask if the battery to body ground is in good shape?
Feb 9, 2023 at 9:24 AM
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LUIS15
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Okay, so that rules out the ignition cylinder and the ignition switch. the thing about ECM is I have no check engine lights on it.
Feb 9, 2023 at 9:36 AM
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STRAILER
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Yep, there is no code for this problem, are you getting power at the starter trigger when in the crank position?
Feb 10, 2023 at 1:19 PM
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LUIS15
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Yes, I think I’m going to have to check the wires when the car doesn’t turn that way, I can figure it out. Because everything is normal when I crank because it turns on, I’m going to check it when it doesn’t crank, I’ll update it. thank you
Feb 10, 2023 at 4:37 PM
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CARADIODOC
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Hi guys. I'm waiting to learn the solution. In the meantime, I haven't seen any reference to the neutral safety switch. Could a vehicle have a backup provision designed in where pressing the brake pedal bypasses or overcomes the defective neutral safety switch or transmission range sensor? Those commonly fail by being intermittent which would explain why the brake pedal isn't needed every time.
Feb 10, 2023 at 5:32 PM