I just installed an under dash diode harness to make my rally sport headlight system work. It instructed me to remove the brown wire from the ignition switch and plug into a connector. The other end of the connector had the new brown wire to plug back into the ignition switch. Turn the key to start and the harness started smoking. Went back and uninstalled and placed the origional brown wire back and now nothing. Thoughts?

Was the diode on the wiring harness exposed instead of being wrapped in electrical tape? It's possible that it shorted out on something underneath the dash. Check for any damage to the brown wire at the ignition switch, also check for any blown fuses.
Make sure that the brown wire is all the way into the connector for the ignition switch. It might not be making a good contact.

The diode harness is new. I rechecked all the connections and they are fine. When I hit the key, I am now getting a clicking noise in the headlight relays mounted to the board. No click of the starter at all.

Are the headlights working? If so........Grab a test light, turn the ignition to the on position and check to see if you are getting power to the starter solenoid via the yellow wire coming from the positive side of the coil. If you have power at that point, check to make sure that all the connections to the starter solenoid are secure, but first make sure to turn the key to the off position, so you do not get any arcing. If all the connections are nice and tight, the problem might be the starter solenoid. Do you know how to jump the solenoid with the positive battery terminal, to the switch terminal with a screwdriver? You must do it with the ignition switch on. If the car starts, then you have a bad starter or solenoid. If it does not start, you have a bad ignition switch.

Headlights work fine. I am getting power to the yellow wire on the solenoid 6.2 on the meter with the key on. The starter does engage when cross over the terminals with a screwdriver. I had the starter and battery tested yesterday and both were fine. Still when I hit the key, I get a clicking noise in all three headlight relays. Would the circuit breaker on this relay board have any affect? If not, do you still think it is the switch? Is there any special order for the relays on the board 1-3? All have the proper wire connectors attached. You are very helpful-- Thanks.

Let me also add that I took out the shifer in the console to have it replated. I did hook up the nuetral saftey switch but the adjuster linkage will need some adjustment. Can the neutral saftey switch cause my starting problem? I have tried to move the shifter back and forth while turning the key and I still get the clicking in the headlight relays with no attempt to start at the starter.

Bypass the N/S switch by using a jumper wire. Take your test light to see which is the hot wire( I believe it's the pink), cross the jumper wire to the purple wire, the one that goes to the starter. It should start right up!

Just to claify. I will run a wire from the switch ( hot wire ) and connect the other end to the purple wire on the starter. Do I connect both ends and hit the key or touch the wire to the starter with the key on?

On the n/s switch there is four wires two small wires are revers lights and two larger wires is park saftey.unplug switch at shifter and put jumper across two large wires which should be purple but make shure trans.is in park or brake is set to prevent car from moving if it starts.Also clicking at relays could be breaker kicking.Bad headlight door limit switch could cause breaker to keep tripping if motor on headlight doors is still trying to run when doors are open or closed.May also be bad relay.Sorry didnt pay close attention you said doors worked fine.Jumper should work to start.If not still could be a bad relay.

Jumped the switch and it turns over!! Took the shifter back out and found that the tang on the lever attached to the shifter had not inserted into the contact support on the switch so it was sitting idle and not moving with the shifter. Thanks so much for everybody's help. This site is extremely helpful.

if you have tilt, try turning the key and moving the steering wheel up and down, because the ignition rod itself has a tendensy to bend. if that doesn't work try pulling the rod that comes out of the switch..sounds like it isn't making complete contact threw the ignition switch.