Got a 94 Bronco 302. 198k miles

Have replaced, checked and rechecked all my major electrical components recently..... Haven't been able to put 1000 miles on the truck this year due to this nightmare... Now scared to take it farther than the end of the driveway

New battery (again... 3rd in 3 years. AGM. Thank goodness all under warranty)
Bench tested alternator (2nd alternator in 3 years... Again yay for free warranty)
new starter (maybe a year ago)
New starter relay (last week)
New ignition/lock cylinder (last week)
New ignition module (under dash. Last week)
New main power (battery to relay and starter. Last week)
New main ground (battery to block/chassis. Last week)
new battery cutoff (ground side. Last week)
New msd coil (couple months ago... No mileage since)
new distributor cap/rotor (same as coil)

So... Still won't start with key... Can only short circuit across relay to start with a screw driver. When starts battery reads 14.4v implying that everything works. Within 2 mins drops to 12v (on voltmeter on battery posts).... Then battery light on dash comes on and reads 8ish volts.

Have removed every unnecessary plug and fuse I can think of including.... A/c (which doesn't work anyway), stock radio, blinkers, headlights, etc.

Ideas of where to look next?

Is it time for a Painless Wiring Harness? If so.... What's the deal with swapping distributors or whatever they say about that

 

When you turn the key to start what happens? Are you in park? If so try it in neutral (with park brake engaged and/or foot on brake).

Regarding the mystery draw, after the two minutes when the voltage drops have you held the rpm's at 2K for a couple of minutes and checked the voltage? Do you need to jump the battery the next day?

 

I've been meaning to try to neutral test, just haven't had time the last couple days. Will try that next. All dash lights come on when I turn key on in park. When I push to start position I lose all dash lights/gauges and the starter won't engage

Yes... Was having a major drain on the battery thus why I installed the battery kill switch. Now no drain overnight! Running up and down the road (or hi idling) makes no difference. Still reading 12 volts. Old battery kept draining and was reading 8ish and wouldn't hold a charge

 

The MLPS contains the Neutral Safety Switch. The Start signal from the ignition switch is fed through those contacts (Park or Neutral position).

If your truck has an anti-theft control module then you have another device that could be causing your issue. This device is between the ignition switch and the MLPS.

 

Yea that's what I was going for with the N start test. Both modules are on the drivers side in the back of the engine compartment. I forget which one, but one of them is under the brake booster.

The draw is another monster altogether. Is the wiring original? Are you losing fuses (burning up)? Does the fusebox look like it's been zapped?

 

Thanks all. I'll check that neutral for sure. No security system

Have never blown any fuses since I've had it

All original wiring harness (I assume... Bought truck 4 years ago). Only wires that have been changed by me are listed above

 

The alternator has a built in voltage regulator that changes ac to dc voltages.It could be you have leaky diodes causing a drain with out the key on and after you start the truck it gets worst. The regulator can be changed w/o changing the alternator . The neutral switch may be your starting problem. Good luck TR