1978 Dodge Ignition/Starter Relay Problems
 

I have an issue, I purchased this 1978 truck and the ignition had been bypassed with a push-button starter. I removed all of the excess wiring (push button included) and installed new ignition/ignition wiring harness, and new turn signal cam and wiring. When I tried to start it, the starter relay sparked, I removed battery cable immediately. I am no expert on wiring, and haynes manual is no help. #1: Does the pos cable from battery and pos cable from starter get connected on same terminal on relay? #2: I assume solenoid cable is connected to post on relay saying sol? #3: I am not sure about the ignition post on the relay, where does it trace back to? Any electrical assistance on this would be greatly appreciated; additionally, starter is new. Any ideas where I could find a diagram for dummies that would show where the ignition/relay/battery/starter wires go to/from?

I don't have a wiring diagram for your vehicle, so the wiring colors may have changed, but they all work pretty much the same

You have three separate important circuits for ignition

You have "ignition run" traditionally dark blue, which feeds "run" power to the coil resistor/ ignition system, to the regulator ign terminal, the alternator field, and the electric choke if used.

You have the resistor bypass circuit, traditionally brown, hooked to the coil side of the ballast resistor, that feeds "hot" battery voltage to the coil during "start."

Then the starter. You havea traditionally yellow or yellow with tracer, comes from the ign switch in "start" through the bulkhead, and to one of the small push on terminals of the starter relay

The other small push on terminal goes down to the neutral safety switch (if auto) or the clutch safety switch (stick) if so equipped. If it is a "stick" vehicle and has no clutch safety, then the other "push on" terminal will be grounded to the case

The big stud/ nut goes to the battery, to the starter main stud, and internally feeds one of the relay contact.

The other relay contact is the big "square" screw terminal, which goes to the small solenoid terminal.

So when you twist the key to "start" the yellow feeds power to the relay coil, and if it is getting a ground on the second terminal, it pulls in, closes the contacts, and runs the starter.

The main points to look out for are --

bad relay coil (won't pull in)

bad relay contacts (might hear it click but no crank)

bad wiring from relay to bulkhead, to ign switch connector or INTERNALLY in ign switch itself

bad wiring from relay to neutral safety switch, or bad switch, or something wrong internally in transmission.

And of course any wiring problems in between

If for example (happened to me) the starter vibrates until the small solenoid wire terminal breaks internally, the relay might click, but the starter won't fire.