Okay, so i'll start from the beginning. I had my brake lights go out, went to check on the cause of the issue. Got them working and tried starting the truck, wouldn't start. Got code reader, it wouldn't even link, so i fried the ECM, replaced it, it will now pull codes and it pulls p0345 Camshaft Position Sensor A Circuit Malfunction (Bank 1). It will start and run like 200 rpm at an idle and sometimes it will start and run fine for a few seconds (30 seconds or less).

(I have replaced both the cam sensor and crank sensor with a known good sensor, no changes)

Got it to run good for a minute (was a fluke) then it left me stranded and wouldn't start back up. The truck wouldn't shift AT ALL. (Transmission shifted extremely smooth before) Im lost as i've never seen a vehicle mess up this way before. SOMEONE PLEASE HELP ME!!!!

I've double checked the grounds 10 times. nothing changed.

 

What kind of Ranger is it?

1983 to 2012 are the years, with Cam sensor and 4 digit trouble code I would guess 1995 or later

And engines from 1995 and up were 2.3l(x2), 3.0l and 4.0l(x2)

 

It's a 1998 ford ranger 2wd, it has the 3.0 and an automatic transmission. Sorry for forgetting to put that :p

 

The brake lights are a separate system from the rest of the electrics

They have power all the time, they are not part of Key on/off, so basically there is a wire from a fuse to the brake pedal switch and then from that switch to the brake light bulbs.
The cab brake light is a direct run from the switch, tail lights run thru the Multi-function switch(turn signal stalk), no other wiring involve, well unless you have trailer lights connected, lol.

So outside of yanking a hand full of wires out I can't see a connection between brake light work and a no start
The ignition switch is right above brake pedal area, if you pulled out its wires starter motor wouldn't work and also a no start

And frying the computer would be a long shot, in 1998 there is nothing in the cab wiring even connected to the computer, all its wires are in the engine bay.

So I would ignore the "all I was doing was fixing the brakes lights" part, not related at all.
Something else is missing from the puzzle.

So if it starts and dies I would say fuel is the issue, or lack of it

Got to ask..............is there gasoline in the tank, NOT on the gauge, can you remove gas cap and push truck back and forth and HEAR gasoline sloshing around?

Next, on the engine is the fuel rail, it feeds fuel to all the injectors, if you look around it you will see a Schrader Valve, looks like a Tires Air Valve because that's what a schrader valve is, might even have a cap on it
And it works the same, press the center pin to release pressure.
1998 Ranger and up will have 60psi fuel pressure
Find the schrader valve and press center pin to see if there is fuel and pressure there, be careful could be 60psi, will squirt a long way
If no pressure turn key on and off 3 times then leave it off, you should HEAR the fuel pump in the gas tank run for 2 seconds EACH TIME key is turned on, it isn't quiet, you will hear a HUUMMM

If you don't then you are getting close to the problem

Now test for pressure at schrader valve again if still no pressure then check Fuel Pump Fuse in engine fuse box, FP Fuse

 

Yes there is fuel, before i replaced the computer it was dumping gas so bad it ran out of the exhaust manifold. fuel pump kicked on. Computer is verified bad, whatever i did, did major damage to this truck.

 

I will post the engine wiring diagrams, there are 4

Check Fuse #13(15amp) in engine fuse box, that powers all automatic transmission solenoids and O2 sensor heaters
Also fuse #6(10amp) thats Keep alive power for computer

One thing to remember for post-Computer vehicles is that 12volt wiring is kept to a minimum, most Controls are done with Grounds.
Auto trans solenoids all get 12v with key on, computer grounds each to activate it
Fuel pump relay is closed by computer grounding it, as are most relays in a vehicle
Fuel injectors are opened by computer grounding them
Spark has always been controlled by Grounding the coil, thats what Points did, grounded the coil

So while a 12volt short can melt wires or hopefully blow a fuse it shouldn't damage components because a short to Ground is normal activation for most devices on the engine.


On pages 1 and 4 are the computer pin numbers for each wire
Google: ford eec v pinout images

That will show you the pin numbering so you can test any wires