So, my trusty 4.0L truck loaded with sheetrock (ok, 6 sheets), decided to just stop. Driving along, then couldn't accelerate, idling kind of rough, I pull over, shut the truck off, try to start it and nothing - no click, no turnover, nothing, like the battery just disappeared. Tow truck puts a jump pack on it (after sitting about an hour) and it fires right up, he drives it up on the tow truck, he tries to take it off, it starts, gets halfway up my driveway and stalls, it will turn over (with two jump packs), but never starts, pump the gas, nothing. I had previously removed the bed of the truck and put it back on.

I suspect maybe something grounded out the fuel pump and killed the battery, after a couple of hours charging (with a questionable charger) nothing when I turn the key. I put an ODB-II tester on it with the hazards on, and the reader kept flashing on and off too like there wasn't enough power in the system for it. I am not a mechanic or electrical engineer, but if someone can point me in the right direction, I would appreciate it!

I do have a multi-meter, battery reads 12.23 V, pretty sure I need a new battery to start. I checked the fuses under the hood, found one burned out for the air bag (surprise!)

 

Battery may be fine, when you Jump a vehicle you are clamping to the OUTSIDE of the battery cables, so if the battery terminals and cables have a bad connection then jumping works but no start with just battery because its NOT connected, terminals are dirty

Clean the battery terminals first, BOTH!!!

Leave negative cable unhooked!!!

Follow larger and smaller Positive battery cables
One will run to a Starter relay on the inner fender, it will be on a post with a nut, remove the nut and clean ALL the wires on that Post, then put them back on and the nut
Put Negative cable on battery, tighten it up

Now try head lights and starting

If that doesn't work then follow the larger Negative cable, to where it attaches on the engine, usually by Starter Motor
Clean that connection

Try starting again

 

Thanks, RonD, gives me something to check tomorrow, did check the battery cables, they are connected pretty solid with no corrosion, but it never hurts to go over then again.

 

Remove them, clean with wire brush

 

So, checked all the grounds, cleaned it all, resecured, everything looks good, getting 12.71 V at all grounds. When my son attempts to start it, no matter the ground point, the battery drops from 12.71 to about 6 V, but nothing happens. The accessories come on, headlights turn on, idiot lights come on, any chance this could be ignition switch? My son climbed out of the truck and he was able to turn the switch without the key in it... Maybe on to something?

 

This probably would have been important to mention, when we tried to start, we heard ticking from under the dash.

 

No, not the ignition switch

And the key is in the ignition cylinder, no wiring there, ignition switch is under steering column above brake pedal area

Reads like starter motor is frozen or shorted inside
Thats a big voltage drop, it should only drop 1.5 to maybe 2volts, so if battery was 12.5v then with starter motor on it would drop to 9.5-10volts max

So pull starter motor and test it

Several relays turn OFF when key is in START position, so "clicks" from under the dash is normal, you just usually don't hear them because of starter motor noise when its working

 

I had the key out of the ignition, and still heard the ticking from under the dash, I may have to break down and call in a professional...

Starter motor could be frozen, but that doesn't explain the stall at the beginning, I may not be a mechanic, but I am pretty sure the starter wouldn't cause the truck to stall unless it somehow engaged, then it wouldn't turn over at all... It's a head-scratcher that's for sure.

 

The "ticking' under the dash is probably battery saver relay, 1995 was first year for that, and the GEM module
Low voltage will cause it to "tick"

The stall could have been for a few reasons, and low voltage can cause it if fuel stops or computer does

Alternator is connected to battery positive post and share the vehicle wiring from there out to the vehicle
When vehicle is running alternator carries the whole load, at 13.5 to 14.5volts, batteries are only 12.3 to 12.9volts so alternator voltage flows TO the battery
When engine is off all voltage comes from battery
So the common point is where alternator and battery positive meet, and power the vehicle

Other common sharing point is battery negative, there is no 12volts unless there is 0volts, battery negative, so another common point BUT...........alternator has its own 0volts in its metal case, so stalling out probably won't be battery negative related

Starter motor may have been drawing too many AMPs for awhile, and this stressed out the 12volt connections enough to cause the stalling and now the starter is over the top on AMPs
Or main battery cables are corroded enough to not be able to pass enough amps, starters need 60-70amps normally, although that wouldn't stall the engine

 

Thanks, Ron, I am spending a lot of time on YouTube checking videos, how to check ignition switch and starter...

 

Mystery solved. The ignition switch was bad, and the fuel pump was bad. Replaced them both finally and it starts right up. I dropped a new battery in too as I couldn't tell the age of it.

 

Good work

Thanks for the update and fixes