I have a 2004 Jeep Liberty and went to jump start it with my welder, have used it before, but for some reason too many volts went through it this time

I have a 2004 Jeep Liberty and went to jump start it with my welder, have done it before, but for some reason too many volts went through it and everything went dead. Turn the key and nothing on dash nothing period. I replaced the BCM and now when I hook up the battery the flashers start and won't turn off. I think a wire must be shorting out or maybe more wires, but I can't find any bad wires. It also blew about 10 fuses when this happened. Any ideas on what to check??

I’m sorry. I’ve read this post a couple of times and I always end up laughing. You tried to jumpstart your car with a welder? You only blew 10 fuses? I wish I could be more help. Hopefully someone will be.

eric1514 said:

I’m sorry. I’ve read this post a couple of times and I always end up laughing … I wish I could be more help.

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There should be a special emoji for this.

Im not laughing, more of an SMH.

I also wish that I could be more helpful, but all I can think is "poor little ECM" !!!

That said, I am not sure if OP meant ECM (Engine Control Module) when he said that he already replaced the BCM (Body Control Module)??

Oh that is craziest thing that I have ever read. A welder? Do you think you used enough volts and amps? I bet most of you wire harness is toast.

Pitneykk said:

Oh that is craziest thing that I have ever read. A welder? Do you think you used enough volts and amps? I bet most of you wire harness is toast.

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No, I can't find any burnt wires, and the ECU is okay, but I still am not getting any power when I turn the key. Unless it broke a wire inside the casing, even the instrument cluster is still good. I just don't know what wires are supposed to power on when I turn the key.

Ericp09 said:

and the ECU is okay

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How do you know that?

That said, maybe you somehow just fried the starter itself…have you checked it by jumping from a separate battery?

Ericp09 said:

No, I can't find any burnt wires, and the ECU is okay, but I still am not getting any power when I turn the key. Unless it broke a wire inside the casing, even the instrument cluster is still good. I just don't know what wires are supposed to power on when I turn the key.

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Does that year have a tipm fuse box

seafish said:

How do you know that?

That said, maybe you somehow just fried the starter itself…have you checked it by jumping from a separate battery?

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Yes, starter turns and cranks engine just fine. Tested ignition switch, also good. It just doesn't get power to instrument cluster when I turn the key, but at the plug for instrument cluster I have 12 volts.

I understand how I sound ******** for how I jump started it, but I am really looking for a solution to fix this.

Ericp09 said:

I understand how I sound ******** for how I jump started it, but I am really looking for a solution to fix this.

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I am much more familiar with the CRD motor, so Im just shooting from the hip here, but Im still unclear how you KNOW that the ECU is completely OK.

That said, if youre sure that the ECU is fine, I would start by checking and/or replace crankshaft and camshaft position sensors that allow the engine to start when turning over. If one or both of the these sensors got fried then the ECU doesn't know when to fire the plugs.

Also you should probably check and/or replace the coil packs…its possible that they got fried too, but Id start with the others first.

Have you tried reading any codes? A simple code reader can be had cheap. You say the cluster doesn't work so you can't tell if you thrown a CEL. A code reader might clue you in to what might have gotten fried.

Ericp09 said:

I have a 2004 Jeep Liberty and went to jump start it with my welder, have done it before, but for some reason too many volts went through it and everything went dead. Turn the key and nothing on dash nothing period. I replaced the BCM and now when I hook up the battery the flashers start and won't turn off. I think a wire must be shorting out or maybe more wires, but I can't find any bad wires. It also blew about 10 fuses when this happened. Any ideas on what to check??

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AI says "
When you turn your key in a Jeep Liberty, the ignition switch activates several distinct circuits depending on the position. To trace or test these, you will primarily look at the wiring harness directly behind the steering column or at the Totally Integrated Power Module (TIPM). [1, 2, 3, 4]
Here are the specific wires and what they control based on the key position:

• ACC (Accessory) Position: The tan wire (Ignition Switch Output Run-ACC) powers on. This sends 12V to the radio, power windows, and lighter. [1]
• ON/RUN Position: The red wire acts as the constant 12V battery power. In the "Run" position, the switch bridges power to the pink/yellow wires (and pink/white wires depending on the year). These power on the fuel pump, ignition coils, engine computer (PCM), and instrument cluster. [1, 2, 3, 4]
• START/CRANK Position: The pink/yellow wires remain active to keep the engine computer alive, while a light blue with red trace wire (or plain green in some variations) engages the starter relay. [1, 2, 3]

If you are trying to diagnose an electrical fault, use a multimeter or test light to check if these wires are receiving +12V when the key is turned."


Just a quick search says that most chips can tolerate up to 24V. I don't suppose you have any idea how many volts you hit it with? In theory I would think you are jumping a low battery and it should absorb the excess, but no idea what happens if it gets overloaded and passes that extra on. A lot of things could have been ruined. Did you replace all the fuses? Check all fuses if you have not. Both fuse boxes.