Today I hooked gauges up to my A/C system on a 2001 Town Country 3.8L AWD and saw the system was full. Trying to diagnose if the compressor works I jumped the low side switch. As soon as I did that the engine shut off and now there is no spark. I have no power to the coil and all the fuses check out good.
Anybody have a clue to what I did or shorted out?

 

Forgot to add it was the blue wire with the green stripe on the 3 pin connector I put power to. I was using a power probe.. I meant to hit the negative switch. not the power.

 

Also forgot to mention I have no injector pulse.

 

Ok, how were you able to tell that? What location switch are you referring to? Did you unhook what you touched together yet? Is this a Powered test light you used?

 

The numbers on the gauges where high.
But my main concern now is how the heck did I manage to kill the engine.
The test light I used is powered. I sent 12V to the wire on the switch and it instantly died.
I've been working on this ever since trying to get spark and injector pulse back. I've cleaned every since ground I could find. Cleaned up the battery terminals.
I've never had a problem like this before with jumping a low side switch. So I'm pretty stumped at this point.
Before I came to this forum I searched for a good hour and came up with nothing related to this.

Thanks for the reply.

 

U shorted out the PCM when u jumped the 5v to the ground or what ever u did u get to buy a new pcm if the fuse is not blown and that's all it is.

 

Hmmmmm... Thats what I was starting to think after reading codes that kept coming back.
Here's the list..
PO118 Engine Coolant Temperature Sensor Circuit High
PO123 Throttle Position Sensor Volts High
P1193 Inlet Air Temperature Sensor High
P1598 Air Conditioning Pressure Sensor High
I've never had an issue like this before when jumping a switch.
If it is the Engine Control Module is there any way to verify it is the issue?
This is certainly a Friday from hell.

Thanks for the help guys.

 

Oh and yes ALL the fuses are good.

 

You shot 12V down a wire on a sensor that is on the 5V reference circuit. Shorting the 5V circuit to ground will take the PCM BUS down and you will lose communication until it's rectified. Pumping 12V into it is not a good idea. We don't use powered test lights for this very reason. They are OK for circuits that don't have modules attached to them, but I just avoid them altogether. There are other ways to test.


DB/DG - PCM C-2 connector PIN 43 is the sensor ground internal to PCM. It is probably damaged so the PCM is seeing the full 5V (high) returning through the signal wires. That's the reason for your codes now. Try taking that wire to ground and see if it wakes up.