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Old 09-28-2019, 01:09 AM   #17
rochvids
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Join Date: Sep 2019
Location: Rochester, NY
Posts: 11
Default Re: Aura won't crank

Quote:
Originally Posted by fdryer View Post
What do you by your last sentence? Some clarification is needed. There are several steps to go thru before starting. In general, two steps; turning ignition ON and then continuing turning to the START position.

1-When ignition is turned on, are all instrument panel lights turned on then off a few seconds later, leaving brake, oil and seat belt light on? If this occurs, you verified all electronics turned on, performed their own power on self tests (ecm, bcm, abs, airbag modules) then turned off indicators. General descriptions at this stage are termed the light test but much more goes on than most know.

2-When turning the ign switch to START, the start circuit is enabled to either send 12v directly from the ign switch to the starter solenoid or a low voltage signal is sent from the ign switch to the bcm or ecm to command it to send a 12v signal to a relay, closing a set of contacts that sends 12v to the starter solenoid (electronic starting circuit). In either scenario, powering the starter solenoid occurs first - the starter solenoid pulls out the starter gear to engage the engine flywheel while closing a set of heavy duty electrical contacts to send battery power to run the starter motor. The starter motor requires a lot of current hence the direct battery cable connection on one starter solenoid terminal. Starter ground is thru its frame connected to the engine block. Engine block ground is the wire attached to it and going back to either battery negative or chassis stud connection. Chassis stud ground connection goes to battery negative. Internal to starter solenoids are a pair of large electrical contacts that close when the solenoid is powered up.

You can try the method described previously to manually power the starter from the fuse panel or go directly to the starter solenoid and momentarily jumper across the battery cable terminal and the small terminal with a single wire on it. This small terminal is the start signal/12v from ign switch or start relay in electronic start circuits. Bypassing electronics or electrical wiring by momentarily jumpering across the starter solenoid two terminals should power up the starter immediately. Beware when under any vehicle when performing a manual starter test. Be sure ignition is OFF to prevent the engine from starting up. All you're doing is separating several issues to find a problem; battery, battery cables, their connections, ignition switch, wiring, one of two starting circuits and starter. Jumpering the starter at the starter solenoid eliminates everything except the battery and battery connections. If the starter runs and turns over the engine, you've cut the possibilities in half. If you are hesitant about being under the engine when shorting the starter terminals, you can attach a length of wire to each terminal extending away from the vehicle to momentarily touch the two ends together for a remote start circuit. Four or five feet of paired wires is sufficient to safely operate a starter without being under the vehicle. It's presumed parking brake is engaged and shift lever in park position. If the starter runs and cranks the engine, your problem is as you thought. If the starter does not run, your problems are with battery, battery cables and their connections.

Thank you for the detailed response. Here is why I think it's narrowed down to the ignition switch or ignition wire, and correct me if I'm wrong. The starter solenoid has 3 terminals. One hot wire coming straight from the battery, one from the ignition switch and the other feeds power to the starter. I understand that the the ignition wire should not have any current until the key is turned to the 'run' position, which is the test that I ran, not to the 'on' position. I connected the positive lead of the multimeter to the end of the ignition wire that plugs into the solenoid, and ground to battery ground. I turn the key to on, dash lights are on, door chime, etc, I turn it to run, lights are out and still no power to the ignition wire. The battery is only a couple of months old and all terminals are clean. I know I have good ground because I tested the positive at the starter and measured ~12.5V and I attached the multimeter ground to different spots including the big wire that's screwed to the engine, the 2 screws in the chassis, the starter, etc.

I did as imaddicted2u said and the starter was cranking as I was touching the positive terminal of the battery.

REWARD EXCELLENCE!

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