This is actually a problem that im having with my 93 Bronco but I can't log onto the Bronco forum for some reason and I need to resolve this ASAP.

First of all the battery is fully charged and has a strong connection. The car starts instantly without the interior lights dimming. If the car is on and I turn the headlights on the car shuts off instantly. Also if the lights are on, the car won't start. I just replaced the ignition lock cylinder(because it was broken) so I know that has nothing to do with it.
I really have no idea what to do. please help! TIA

 

Moderators I understand if you have to move this thread but I wasnt sure where to put it where it would actually be read. I need to get this vehicle working since I have to go to work even with 2 feet of snow outside.

 

well there's one of 2 problems.

Your alternator is getting bad and your lights sip just enough power to dip the voltage below what the computer can run on or...

Your lights are somehow wired into your ign circuit.

 

Do the headlights light up?

 

Ya the lights work fine. Thinking maybe it was a ground issue I put a ground from the firewall to the bell houseing. I also just replaced the battery terminals and the ground wire for the battery. Tomorrow im going to clean up any ignition components I can get to easily. How do I determine if its the alternator? I suspect something else since I can run plenty of electrical components without the interior lights dimming like they commonly do.

 

If u turn the lights when ur car is not running, and turn the key on,can u hear the fuel pump run? Did this start when u replaced the ignition switch?

 

It was the ground wire for the computer. Ground wire from near the computer to where the battery ground is located was nearly disinigrated. Replaced the wire, issue resolved. Thanks for your help everyone.