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How to diagnose between starter or solenoid as problem?

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Old 09-16-13, 11:04 AM   #16
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Originally Posted by Habious View Post
I think this is an absolutely terrible idea!!

Mainly because, if he takes this advice...*I'm* the gonna be the "someone" with his head stuck under JohnnyCake's car while he's cranking it!!

...And I've already climbed inside his trunk. I think that's enough for one friendship.
LOL

What do you think is going to happen? Flames will jump out? The engine will blow up?

If you are worried, then you turn the key and let him stick his head under the hood to listen.

Other than keeping fingers, long hair and clothing away from moving parts (belts, pulleys, fan blades) and not touching the battery terminals or exposed hot surfaces there really is a no great danger under the hood.

I won't ask what you were doing in his trunk ................
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Old 09-18-13, 06:03 PM   #17
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Originally Posted by jkeifer3 View Post
You're right about that. If the starter motor is connected to the battery, even if the battery is low, it would suck the life out of it and the lights would dim, the solenoid would drop out, and the sequence would probably start all over again.

It could be a bad solenoid not passing juice to the starter motor, the wiring to the starter motor or the motor itself. There's not much else.
Not true. When the solenoid closes it completes the circuit to deliver voltage across the leads of the starter motor.

If the brushes in the starter motor do not make contact with the commutator the INTERNAL circuit in the starter motor is not complete and no current will be drawn from the battery and thus no dimming of the lights.

Just a click. That's it.
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Old 09-21-13, 06:41 AM   #18
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Originally Posted by SC43052 View Post
Not true. When the solenoid closes it completes the circuit to deliver voltage across the leads of the starter motor.

If the brushes in the starter motor do not make contact with the commutator the INTERNAL circuit in the starter motor is not complete and no current will be drawn from the battery and thus no dimming of the lights.

Just a click. That's it.
Of course it's true. My first paragraph assumes that the starter motor is good completing the circuit.

My second paragraph states that the problem could be the solenoid, the wiring to the motor or the motor itself (including bad brushes or commutator).
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Old 09-22-13, 12:17 AM   #19
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Originally Posted by jkeifer3 View Post
Of course it's true. My first paragraph assumes that the starter motor is good completing the circuit.

My second paragraph states that the problem could be the solenoid, the wiring to the motor or the motor itself (including bad brushes or commutator).
If you are saying that in your post you were only stating a hypothetical, that given a good starter motor, good solenoid and good wiring, when the starter motor is delivered voltage and presents a load to the battery the lights will dim, then yes I agree with you and I stand corrected.

I was confused because you were responding to the earlier poster stating that the lights must dim if the battery is weak. You stated "if the motor were connected to the battery" which seemed to be an elementary way of describing the circuit, and led me to believe you thought the motor was always in the circuit.

Further confusing was your first paragraph where you say you assumed the motor is good, and if voltage is delivered to the motor it will present a load to the battery and dim the lights, in spite of the fact that the OP states he hears a click (which one would assume is the solenoid engaging and delivering voltage) and he also claims there is no dimming of the lights (one would assume this means no starter motor load). Confusing when you ignored the OPs description.

Then in the second paragraph you state it could be the solenoid (OP states he hears it every time the car doesn't start) the wiring to the motor (unlikely because most of the time the car does start) or the motor itself.

I assume you agree with me that the starter motor itself is the likely failure mode IF the click the OP hears is the solenoid engaging.
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Old 07-22-14, 05:18 PM   #20
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I continue to have this problem every few months. I think this thread has one of the best discussions I've read to help diagnose a "no crank" but "good battery" problem.

Here's something I just learned that might be helpful in determining whether the ignition switch or the park/neutral safety switch is part of the problem.

If the park/neutral safety switch is not enabled, then upon turning the key, the lights on the NAV and climate control will go off (NAV power cycles), BUT the dash lights stay on.

If the park/neutral switch is engaged (i.e. you are in park/neutral and the car knows that), turning the key will cause the dash lights and the NAV and the climate control to go dark during the key turn process.

I think this helps diagnose as follows.

Turn key:
1. If no change in any lights (dash/NAV/Climate) = ignition switch itself is bad.
2. If NAV/Climate lights go out, but dash light stays on = park/neutral safety switch is not engaged (i.e. car does not think it is in park/neutral) but ignition switch is good
3. All lights go out, still no crank = something farther down the line, but safety switch and ignition switch are good.
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Old 07-23-14, 05:25 PM   #21
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Your logic makes sense.

The ECM uses relays to remove the most or all electrical loads during starting to be able to devote the bulk of the battery voltage to the starter motor.

If the click you are hearing is the solenoid engaging, I still think it is the starter motor brushes which are making an intermittent connection. Only strange part is that your example appears to be remaining very intermittent. Most times once starter motor brushes start to exhibit signs of wear and intermittent starting they get progressively worse, with non-starting episodes growing more common.

It is a shame that the engine bay holds "ten pounds in an eight pound bag" and the starter is so inaccessible. Makes me pine for the old American cars where checking the voltage on the starter was just sliding under the car and changing the starter was child's play.
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Old 08-13-14, 04:45 PM   #22
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Default Starter or solenoid ?

I have taking all of your suggests and I'm clueless. New starter, new alternator, new ground cable and new battery car still will not start? Everything powers on the inside but no start? What should i do next other than part out my baby?
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Old 08-14-14, 06:54 AM   #23
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Originally Posted by loudSC400 View Post
I have taking all of your suggests and I'm clueless. New starter, new alternator, new ground cable and new battery car still will not start? Everything powers on the inside but no start? What should i do next other than part out my baby?
When you say "will not start" I assume you mean the car is not "turning over" or cranking at all. What exactly happens when you turn the key?
1. Is there any change in any lights (dash/NAV/Climate)?
2. If NAV/Climate lights go out, do the dash lights stays on?
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Old 08-14-14, 06:54 AM
 
 
 
 
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