Wiring problems 82 ford fairmont futura 2 -door v-6 motor. new battery, solenoid, battery cables, alternator, ignition module, and relay. car starts, but won't stay running. seems to be running on battery. think problem is there is no return power to battery from alternator, but not sure where to connect wire. have positive wire connected to positive terminal nothing is connected to ground connection on top of alternator

Basic operation of a starter:
Your engine's starter motor is an electrical motor that is used to rotate the engine in order to get it to fire up. This motor draws a large amont of current from the battery (in the order of 70 Amps and up). In order to supply power to the starter a solenoid is used, it acts as a switch between the battery and the starter motor. This solenoid also engages the starter gear with the engine's flywheel and disengages it once the engine is started. Because the circuit for the solenoid also draws a heavy current a further relay is needed to control it.
The diagram below shows the electrical layout of the starting system.

• i : Battery
• ii : Starter relay(located in the relay box in the engine compartment)
• iii : Starter solenoid
• iv : Starter incorporating solenoid and motor.
• v : Engine
• vi : Battery earth cable
• vii : Engine earth cable
• viii : Ignition fuse
• ix : Starter fuse
• x : Solenoid to starter supply cable
• xi : Ignition switch
• xii : Starter motor

When the ignition(xi) is turned it supplies power from the battery through fuse (viii) to the starter relay(ii).
The starter relay activates and supplies power to the starter solenoid(iii) via fuse (ix)
The starter solenoid activates and connects power from the battery to the starter via a short cable(x) between the solenoid and starter motor. This allows the starter motor to turn.

General trouble shooting.
Turn the ignition off.
1/ First you need to check that the fuses are intact.
Keep the ignition off. Place the vehicle in Neutral. Chock the wheels and engage the parking brake.
2/ To prove the starter motor, connect power from the battery positive to the cable (x). This must be done with jumper cables. Touch the jumper cable to the connector on the back of the solenoid where cable (x) connects. Take care not to short circuit the jumper cable to the engine or vehicle body. It can be a tight fit and might not always be possible. If you hear the starter motor spin then it is working along with the engine earth cable. If not, connect the negative lead of the jumper cable between the battery and the starter motor body or any other bare piece of metal on the engine and put the positive lead on cable (x) again. If the starter motor does not spin it needs to come out for repair/replacement. If it spins check both the battery earth cable and engine earth cable and repair where nescasary.
3/ Once the starter motor has been proved move on to the solenoid. Remove the thin wire from the solenoid. Using a small piece of wire, connect battery positive to the connector where you just took off the wire. The solenoid should kick in and the starter motor will turn the engine. If the solenoid does not kick in, remove the starter for repair/replacement of the solenoid. If the solenoid kicks in then replace the starter relay.

If the starting circuit still does not operate the fault will be in the wiring. This needs reasonable expertise and if you dont have a voltmeter handy is not advised.
Bear in mind on automatic transmission vehicles there is an additional switch (Mode switch) wired in between the ignition switch and the starter relay. This switch is on the transmission itself and if faulty will not allow the starter to operate even if steps 1 to 3 were successfull. The same goes for the anti theft/immobiliser system.


The following is specifically for Isuzu Trooper and Rodeo :

• i : Battery
• ii : Starter relay(located in the relay fuse box in the engine compartment designated X-17)
• iii : Starter solenoid
• iv : Starter incorporating solenoid and motor.
• v : Engine
• vi : Battery earth cable
• vii : Engine earth cable
• viii : 10A Starter fuse C-1(Fuse box: LH footwell on LHD vehicle, RH dash on RHD vehicle)
  
• x : Solenoid to starter supply cable
• xi : Ignition switch
• xii : Starter motor
• xiii : 80A Main fusible link FL-1(Relay fuse box)
  
• xiv : 50 A Key SW fusible link FL-2(relay fuse box)
  
• xv : Mode switch(A/T only - mounted on the side of the transmission) and for 6 cylinder manual transmission engines this is the clutch start switch mounted on the clutch pedal.
  
• xvi : Anti theft system
  
• B2 : B2 on ignition sitch
• ST : ST on ignition switch

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