Electrical Confused about starter solenoid

Renob89gt

Member
Apr 25, 2020
27
3
13
Ohio
Positive battery cable was looking rough and I noticed a small crack in starter solenoid. So I replaced them, and bout a new motorcraft solenoid. Well now I have a draw on the battery that is leaving me with a dead battery after a couple of days. Out voltmeter on last night, 12.3. then this morning it was 12.0. I put all the wires on the same side they came off of. I'm confused as to how it. Would be creating a draw on the battery.
 
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Solenoids are simple. They have one little wire that tells it to open, and when it does it allows current to run from the battery cable to the starter cable. The only thing I think could be causing your drain would be you got a bad solenoid. It's making a superficial connection internally. Disconnect the starter cable from the solenoid and the little wire and check if there is any current exiting to the starter cable side.
 
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It's pretty easy...the wire from the battery goes on the side with all the other wires. Only the wire to the starter is on the other side. The little red / blue stripe wire is the little one that goes on the little post.

Post a pic of it and we'll verify it's done right.
 
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Positive battery cable was looking rough and I noticed a small crack in starter solenoid. So I replaced them, and bout a new motorcraft solenoid. Well now I have a draw on the battery that is leaving me with a dead battery after a couple of days. Out voltmeter on last night, 12.3. then this morning it was 12.0. I put all the wires on the same side they came off of. I'm confused as to how it. Would be creating a draw on the battery.


Starter solenoid wiring for 86-91 Mustang
attachments\52294



Starter solenoid wiring 92-93 Mustang or earlier Mustang with upgraded high torque mini starter.
attachments\53216




Finding current drains

Typically it is something draining the battery. Small things like glove box or courtesy lights are often the culprits. If you have an aftermarket stereo or alarm system, it is also suspect.

The ideal method is to disconnect the negative terminal, and connect a Digital Multimeter (DVM) between the negative terminal on the battery and the negative cable. Set the DVM on a low current scale of 2-5 amps if it doesn't auto range. Watch the current draw, and then start pulling out fuses. When you see a sudden drop in the current, that circuit is the likely culprit. Note that the computer, radio & clock will draw less than 1/10 amp to keep the settings alive.

Using the negative side prevents nasty accidents like shorting the wrench to ground while disconnecting the battery cable. Electrically, the test will work with either positive or negative battery cable.
 
Solenoids are simple. They have one little wire that tells it to open, and when it does it allows current to run from the battery cable to the starter cable. The only thing I think could be causing your drain would be you got a bad solenoid. It's making a superficial connection internally. Disconnect the starter cable from the solenoid and the little wire and check if there is any current exiting to the starter cable side.
I'm new to this thing, how exactly do you check the current?
 
Starter solenoid wiring for 86-91 Mustang
attachments\52294



Starter solenoid wiring 92-93 Mustang or earlier Mustang with upgraded high torque mini starter.
attachments\53216




Finding current drains

Typically it is something draining the battery. Small things like glove box or courtesy lights are often the culprits. If you have an aftermarket stereo or alarm system, it is also suspect.

The ideal method is to disconnect the negative terminal, and connect a Digital Multimeter (DVM) between the negative terminal on the battery and the negative cable. Set the DVM on a low current scale of 2-5 amps if it doesn't auto range. Watch the current draw, and then start pulling out fuses. When you see a sudden drop in the current, that circuit is the likely culprit. Note that the computer, radio & clock will draw less than 1/10 amp to keep the settings alive.

Using the negative side prevents nasty accidents like shorting the wrench to ground while disconnecting the battery cable. Electrically, the test will work with either positive or negative battery cable.
For sure have it all wired up right. Starter cable on the right and every thing else to the left with the small starter wire to the little post
 
Considering it was fine before no swapped out the new parts, I guess it goes to show always check the simple things. Had battery tested and it had a cell going out I guess because new battery and everything is fine. Just seems weird since there wasn't an issue before the new parts. Thanks for the help gents.
 
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