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Delete the solenoid in your Mustang


Active Member
This is only meant to be done to cars that have a mini-starter already installed or if you are upgrading to one. This will not work on an original starter.

First gather up the parts you will need. I bought mine from Waytek but you can source them elsewhere. Waytek has a 50 piece minimum order quantity on the terminals. It's never a bad thing to have some extras.
  • http://www.waytekwire.com/item/75280/MINI-RELAY-CONNECTOR/

  • http://www.waytekwire.com/item/75311/HIGH-CURRENT-MINI-RELAY-12V/

  • http://www.waytekwire.com/item/32074/TERMINAL-FOR-RELAY-CONNECTOR/

  • http://www.waytekwire.com/item/31073/TERMINAL-FOR-RELAY-CONNECTOR/

  • http://www.waytekwire.com/item/47213/JUNCTION-BLOCK--87--STUD-RED/

You will also need some 12ga and 14 ga wire.

Start by disconnecting the ground cable to the battery and removing your old solenoid.

Install the red junction block. (power lug) Place it so the existing cables will reach it unless you want to build custom cables. Connect all the cables that come off of the battery side of the solenoid here as well as the big cable going to your mini-starter.

Take the brown wire from the I terminal or the old solenoid, fold it back and tape it to the harness. Because this wire is spliced into the hot wire for the coil it will have power to it. Make sure you completely tape it over or cut the end off and heat shrink the cut.

Take the red/blue wire from the S terminal of the old solenoid and cut the end off. This wire will connect to terminal 87 of the relay. You can use the 14-16 female terminal for this wire. Solder and heat shrink the connection.

Use 12ga wire to make a wire to go from the power lug to terminal 30 of the relay. You will need an 3/8 opening eyelet on the end going to the lug and a 10-12ga female terminal on the other end. Solder and heat shrink both ends.

Make a ground wire the same way you made that previous wire and put it in terminal 85 of the relay.

Take the wire that went from the starter side of the old solenoid and cut the eyelet off. Wire this to terminal 87 of the relay using the same solder and heat shrink method as you did previously.

That's pretty much it.

Here's a diagram of how it should be wired.

BTW, don't get any crazy notions that you can keep the brown wire in the circuit by using a relay with two 87 terminals. The 87 terminals in those relays are physically connected together inside the relay and will provide a path to ground through the starter. Your car will start and run only as long as the relay energizes the coil wire with 12 volts. When the relay de-energizes, the resistor wire will short to ground through the relay and starter. Your coil voltage will drop to about 2 volts and the car will not stay running. Trust me on this.