Zetec Starter Connections

[Ralph Morgan]

Making final electrical connections on the Zetec installation (in live axle 4 speed - replacing a 1700 Crossflow) I'm stuck on connections to the starter motor (equivalent to Halfords 407/Lucas LR146 from local parts factor). This has 3 terminals, whereas the old unit (and any others I've seen) only had 2.

 

One connection is obviously the control feed to the solenoid, and the larger of the others for the power feed from the battery live terminal. What's the third one for?

 

Initial thoughts are that it's a direct earth conection, to be linked to the battery negative (it has zero resistance to the starter body), but can anyone confirm this or give the correct answer?

 

 

[allen]

Ralph,

 

One connection is not used - it goes live when the solenoid is energised - i.e. bridging both hefty terminals will start the motor without intervention of the solenoid.

 

Allen

[felix.klauser]

In some applications there is a ballast resistor in the supply line to the coil. When the ignition key is turned the solenoid closes the circuit to the starter motor. This results in a voltage drop within the car which as far as the coil goes is compounded by the balast resistor so a second circuit is closed by the solenoid to supply battery voltage straight to the coil while cranking. Not needed for a Zetec and indeed most 7's I would have thought.

[Revin Kevin]

Ralph

Save the hassle re install your proper engine.

 

Revin Kevin Crossflow.