Car won't start, need help troubleshooting!

[Chillin014]

To cut straight to the chase:
In the ACC and ON positions there is no response. The key-in-ignition buzzer sounds but the radio does not turn on, and the car does not start. No clicking, or turning from the starter. NOTHING. The headlights turn on and the interior lights but like I said, the a/c nor the radio or any other electronics seem to be getting power. The battery is fully charged, the car has been sitting for awhile as I've been installing a new transmission but it started fine every time. Since the last time I started the vehicle I have :
-Welded a panel to the floor pan
-spilled transmission on top of the engine
-Disconnected my wideband O2 unit which was mostly just a bunch of ground wires to a grounding terminal.

I stuck a screwdriver between the starter terminals and it turned over fine. So I know its getting power. I checked all the fuses and they appear to be fine. Could the ignition switch have gone bad somehow? I am not sure how the radio and a/c are wired up but all of these things seem to have gone out at the same time and I'm just not familiar with the wiring. Should be an easy diagnosis for someone who knows!

I appreciate any advice or help!

 

[8secChevy]

Did you disconnect the battery before welding? If not you can cause damage to the relays, and fuses.

 

[Chillin014]

Yes, it was disconnected but I have read that it really does not make a difference whether the battery is connected or not. I realize something could have been damaged from welding but I don't have a wiring diagram for my vehicle that shows what exactly is between the fuse box and the radio, a/c controls, and starter that is preventing power from getting there. The ignition switch is a just switch, that's the only thing I can think that may have gone bad...

I actually found a wiring diagram online and it does appear that everything goes through the ignition switch...

 

[gman415]

The purple wire on the starter goes straight to the switch(some have neutral safety switch on the shifter, but I don't remember if these cars do). Put a test light on it at the switch and try to start, if you have light there it is a broke circuit between there and the starter. If not, see if you get light on one of the other wires at the switch. If yes then probably the switch. If not then it may by a fusible link on the pink(or red?) wire down by the starter.
http://www.maliburacing.com/wiring_diagrams/StarterSystem.jpg

 

[Chillin014]

Okay thank you. I will have to figure out how to remove the switch and ignition cylinder to diagnose it I suppose. I initially thought fusible link as well but its not just the starter that isnt running its like everything dependent on the ignition switch.

 

[gman415]

I'm thinking fusible link as well, I would just go ahead and see if you had "light" on the side of the link opposite the starter.
The red wire with the link goes from the starter to the fuse box and the ign. switch.

 

[gman415]

If it shows good then check the switch.

 

[Chillin014]

Just as an update it turned out that I melted the wire going from the battery to the starter from the welding. I didn't realize power went from the battery to the starter and then into the car. Wasted my time and money replacing the damn ignition switch too!!