How to bench test starter motor.
#1
How to bench test starter motor.
Gentlemen,
I just took the starter motor off my 2000 Expy and I want to bench test it to confirm that it needs replacing.
The ground (black) cable was connected to one of the starter motor body mounting bolts, so I can use the body as ground.
There are three connection posts on the solenoid:
- one with a little wire that goes directly into the starter, and that I haven't touched.
- a small post that had a smaller black wire in a braided jacket to it
- a larger post that had the red (positive) cable to it.
When it was on the vehicle, turning the key would cause the solenoid to actuate, but the starter motor didn't turn. Now that it's off the vehicle, I can't even get the solenoid to actuate. So I figure I'm just not applying 12v to the correct posts.
Anyone?
Thanks.
I just took the starter motor off my 2000 Expy and I want to bench test it to confirm that it needs replacing.
The ground (black) cable was connected to one of the starter motor body mounting bolts, so I can use the body as ground.
There are three connection posts on the solenoid:
- one with a little wire that goes directly into the starter, and that I haven't touched.
- a small post that had a smaller black wire in a braided jacket to it
- a larger post that had the red (positive) cable to it.
When it was on the vehicle, turning the key would cause the solenoid to actuate, but the starter motor didn't turn. Now that it's off the vehicle, I can't even get the solenoid to actuate. So I figure I'm just not applying 12v to the correct posts.
Anyone?
Thanks.
#2
Never mind - figured it out.
With ground to chassis:
- 12v directly to the post with th little wire going into the body should drive the motor
- 12v to the small post should actuate the solenoid
On mine, both functions are hit and miss. That is, sometimes they work, sometimes they don't. Even with what I believe are good connections. Like it's stuck. Looks like I was lucky and it failed in the driveway instead of in a parking lot a hundred miles from home.
With ground to chassis:
- 12v directly to the post with th little wire going into the body should drive the motor
- 12v to the small post should actuate the solenoid
On mine, both functions are hit and miss. That is, sometimes they work, sometimes they don't. Even with what I believe are good connections. Like it's stuck. Looks like I was lucky and it failed in the driveway instead of in a parking lot a hundred miles from home.
#3
Sounds like one of those starter-mounted solenoid type starters. Many parts stores have setups where they can bench-test it for you, but it looks like you already figured it out. Starters have so much torque that I'm a little weary of setting it on the bench in the garage and trying to run it.
#4
#6
Since the gear is not engaged to anything but air, there is not much torque to worry about. Ive tested many starters on the garage floor. They just move a little bit. One important warning (no I did not do this myself), DO NOT TOUCH THE STARTER DIRECTLY TO THE BATTERY POSTS. Batteries give off hydrogen and oxygen when they are working and any spark can cause the battery to explode.
Jim
Jim
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