ignition switch or wires not right in 14 pin connect
 

I have a 1978 sc just put a 1983 3.0l in when turning the key just to the on position the starter engages. I wasn't sure if I had the wires right in the 14 pin connection..however I checked and do have all the colors corresponding.. yellow to yellow red to red etc..could it be short...how can I tell if its the switch?

14-pin connector.....
 

kmoqu,

Pin #1 (yellow wire) should have no power when the ignition switch @ ON position. The yellow wire going to starter should have no power until you turn the ignition switch @ START position.

Check this pin #1 first:
1). No power when IS (ignition switch) @ OFF.
2). No power when IS @ ON position. This is where your problem now!!!!

Use a 12-volt test lite to trace the power. Keep us posted.

Tony

Good morning Tony, Alright; with switch off:
No power to yellow wire at pin
No power to yellow at starter
with switch just on : power to yellow at pin
power to yellow on starter
I know you told me that there should not be power at starter in the just on mode however there is....?

If you have power at the yellow starter wire with switch in 'RUN' something is wrong.

But it may not be the switch, it could also be a short somewhere in the harness that's backfeeding the power to the yellow wire.

I'd remove the switch from the car and test it with an OHM meter to be sure it's the switch.

Or do the inverse, unplug the harness from the switch and apply 12v directly to pin 'x' and '15'.

You can do this by jumpering:
- pin 30 (RED Wires Hot at all times) to pin 'x' (red/yellow)
- then do pin 30 to pin '15' (red/black)

But I suggest a simple ohm meter test to the removed electrical switch and simply measure resistance between pin 30 and pin 50 and rotate the switch through it's positions. You should only have continuity with the switch fully turned to the start position.

You can remove just the electrical portion of the switch without removing the entire ignition mechanical portion. It's done from the back side of the dash.

After putting in a different switch I had the same problem..after hours of searching for a short..i went to pull out the round relays in the fuse panel and the plastic cover came off ..wouldn,t you know it the relay was cooked together I pried it apart stuck it back in and the short was gone then i had a beer with a smile!!! Thanks for everyone's help

I assume this was the starter relay? or what relay was it?

I suggest you really clean the contacts with 600 grit sandpaper of those stuck contact points. Or better yet replace the relay.

Sal..I ordered new relays...

there is no starter relay. the start wire does go the FP relay, but i dont see how 12v can get to it.
the start signal also goes to the heater blower relay.

i will never understand why porsche did their wiring the way they did. its a mess.