Revised 30-Jan-2009 to reorder checklist and add cleaning procedure for connections.
Since some of the tests will bypass the safety interlocks, make sure that the car is in neutral and the parking brake is set. Becoming a pancake isn’t part of the repair process…
1.) Will the car start if it is jumped? Then clean battery terminals and check battery.
The battery posts and inside of the battery post terminals should be scraped clean with a knife or cleaner tool.
Since you are new to all this, see http://www.secondchancegarage.com/public/159.cfm for a how to clean battery terminals tech note.
The clamp on with 2 bolts battery terminal ends are a know problem causer. Anyplace you see green on a copper wire is corrosion. Corrosion gets in the clamped joint and works its way up the wire under the insulation. Avoid them like the plague...
A voltmeter is handy if you are familiar with how to use it to find bad connections. Measure the voltage drop across a connection while trying to start the car: more than .5 volts across a connection indicates a problem.
2.) Check the battery to engine block ground down near the oil filter, and the ground behind the engine to the firewall. All grounds should be clean and shiny. Use some sandpaper to clean then up.
3.) Jump the big terminals on the starter relay next to the battery with a screwdriver - watch out for the sparks! If the engine cranks, the starter and power wiring is good. The starter relay is also known as a starter solenoid.
4.) Then pull the small push on connector (small red/blue wire) off the starter solenoid (Looks like it is stuck on a screw). Then jump between the screw and the terminal that is connected to the battery. If it starts, the relay is good and your problem is in the rest of the circuit.
5.) Remember to check the ignition switch, neutral safety switch on auto trans and the clutch safety switch on manual trans cars. If they are good, then you have wiring problems.
Typical start circuit... Diagram courtesy of Tmoss &Stang&2birds
6.) Pull the starter and take it to AutoZone or Pep Boys and have them test it. Starter fails test, then replace it. If you got this far, the starter is probably bad.
Starter solenoid wiring for 86-91 Mustang
Starter solenoid wiring 92-93 Mustang or upgraded high torque mini starter.
i have a battery charger hooked up when i turn key ill i hear is a loud click. I know you guys are trying to help me but im am really new with all this never happen to me i tighten the connections to battery terminals still clicks i dont know what to do i guess im walking to work
Is the starter clicking or the solenoid?
I dunno how automotive savy you are so if that was jibberish to you, is the clicking coming from the Drivers side fender right behind the battery, or is it coming from down on the bottom of the motor on the passenger side?
Turn the key to the on position, put car in park (or neutral, have a helper push in the clutch if 5 speed) then walk around to the starter solenoid and touch a screw-driver to both large poles (where the wires are attached). It will spark like a mofo, but if it just clicks then the starter is shot. If it jumps the starter (car tries to start) then the solenoid is shot (cheap and easy fix). Jrichker's post is from the bible of "why wont my car start" so follow those directions real slow and careful if what I told you doesnt do anything for you.
Matt