Coil Test

A coil works by becoming magnetized when powered. The magnetism shifts a valve, which switched the lift from Down to Up, or releases a valve that locks the hydraulics. Older lifts had 12V coils, which energize with 12 Volts. With a low battery, the coils would stop working. Starting in late 2002, lifts have 10V coils, which are less sensitive to a low battery. See Powerpack Component page to see photo of coil. One can hear the coil moving a valve if the starter solenoid is disconnected so the motor does not run. Testing a coil is simple, and replacing a coil is a 2 minute job, even for an end user.

A SunLift has an Up Coil which is energized when pressing the Up switch, and a Down coil which is energized when pressing the Down switch. It is best to test using the switch instead of the transmitter to eliminate the RC as a potential cause. Sunlifts prior to 2002 use a black square coil. Current models use gold cylindrical ones. Both are interchangeable.

A FloatLift has two Down Coils that are electrically connected, and are energized with 12V when the Down switch is pressed. The third coil operates a Locking Valve, which prevents the floats from drifting. The Locking coil is energized when either the Up or Down switch is pressed.

To Test Coil:

  1. To do a quick check, hold a wrench, or other steel, against the side of the coil. The coil will not be magnetized without being energized, and will be magnetized when energized. See Powerpack component page to understand which coil is which.
  2. To test the strength of the coil, remove the upper retaining nut, and hold the coil about a 1/4 inch over the seat. When operating the coil, the coil will pull down with almost enough force beyond your grip.
  3. If the energized coil has no magnetism:
    • Measure Voltage over coil. If no voltage is measured verify the following:
      • RC unit is completely plugged into wire harness
      • Coil power wire is attached
    • If power is measured but coil does not magnetize when energized
      • Verify the coil has good ground by measuring 12V from the Positive terminal of the battery, to the nut of the coil.
      • If the coil has a bad ground, check the grounding strap to the pump. (pre-2004 pumps ground coils through contact with the manifold. Post-2004 pumps directly ground coils starter solenoid and the starter solenoid is grounded to the battery ground on manifold)
      • If grounding strap is ok, and the manifold is grounded, try removing, cleaning and reseating the coil.
    • Replace the coil, if it appears that it has no or light magnetism when properly energized. Water intrusion is the most likely cause of a bad coil. Look for other evidence for water, and keep an eye out for other components going bad due to soaking, such as other coils, starter solenoid, and RC. Use Hydraulic spec table to replace with the correct coil.