Electrical Confused about starter solenoid

Motorsport71 said:

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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jrichker said:

Starter solenoid wiring for 86-91 Mustang

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

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.

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