Troubleshooting single and dual coil solenoids requires a systematic approach, whether you pull the solenoid out for bench testing or test it while installed. The most common solenoid "pulls" the energized plunger in toward the solenoid and can be switched on internally or externally. Push solenoids push the plunger out and can only be externally switched. The most common solenoid is used within your starter. It is an "energized-to-run" application, meaning when you turn your ignition key to on, the solenoid energizes to turn on your starter, which in turn, starts your engine.
Analyze the symptoms of the problem. Determine whether your car houses a single or dual coil solenoid.
Visually scan the solenoid and its immediate setup. Broken parts, like a torn rubber boot, can allow dirt to coat the plunger, decreasing its efficiency by increasing friction and drag.
Check for broken wires, blown fuses, loose connections, pungent odors and misaligned mounting. Your solenoid may be burned out. Misalignments reduce your solenoid's energy to force ratio.
Check the voltage. Disconnect solenoid, apply power. If the solenoid doesn't pull in, check to see if there is enough voltage getting to the system. Readings should be a minimum 10 Vdc on a 12 Vdc system and 20 on a 24 system. If the readings are unacceptable, the battery may need to be replaced. If readings are good, but the solenoid doesn't pull in, then bench test it.
Check to see if the solenoid is wired to the starter's "S" terminal directly or by relay. If it is, the pull coil is incorrectly wired and may negate your manufacturer's warranty. Check your manufacturer's manual for any specific testing to check the connection.
Measure coil resistance using an ohmmeter. The solenoid must be at room temperature (70 degrees Fahrenheit/21 degrees Celsius) before checking. Refer to your manual for your specific wire color schematic and coil resistance value chart.
Check the linkage setting. The linkage connects the plunger to the engine control lever. If misaligned, the linkage will not allow the solenoid's plunger to bottom out, causing unresponsiveness.
