On my 82 when the key is in start it sends 12 volts to the starter to start the car. It also sends 12 volts out to other critcal circuits such as ignition and relays/pumps etc. The only difference between start and run (on) is the starter and some non-essential circuits such as wipers, blower motors etc. If the car starts in start and then stops in run, it is probably the ignition switch electrical contacts. Here is the layout of the switch.

Blue/Yellow wire to term #15 on switch for essential circuits (ECU,Fuel Pump Relay etc)

Yellow wire on term X to feed non-essential for starting circuits (wipers, blower etc)

Blue wire on term 50 that goes to the starter.

Red wire on term 30 feeds switch from battery


RUN INFO ON IGNITION SWITCH:

Off postion= No voltage (except red wire from battery)

Accessary postion= Voltage on Yellow only

On (Run)= Voltage on Yellow, Blue/Yellow only

Start position= Blue/Yellow, Blue only

Most likely is the Blue/Yellow is not getting voltage in the On position. If you have a voltmeter give them a test. Get back to us if you need more info. Hope this helps

Mario



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'I've always been crazy, but it's kept me from going insane' Waylon Jennings