I have a 2003 Jeep Cherokee Laredo (4.7L) AWD that started having some issues a few months ago and has gotten worse. Initially the gauges started jumping around when the vehicle was running which made me believe that there was a grounding issue. Since my son had the vehicle in another state I was not able to do any troubleshooting. Soon the vehicle began to throw a Check Engine light but repeated attempts to the auto parts store to have them read the code provided no code for the light. The vehicle has become more erratic. Sometimes the gauges are jumping around when the key is not in the ignition. Mainly now the vehicle goes completely dead. When the key is inserted there is NO power. No lights, no buzzers, nothing. Its like the vehicle doesnt have a battery. I had my son pull the cables from the battery and ground them together to reset the computer. This has been working but sometimes it may require several attempts before the vehicle will start. BTW when it starts it runs perfectly without issue.

We were trying to start it on Friday and this is the first time I have been able to witness what my son has been telling me. NO power, so we pulled the terminals and reset the computer. It took 3 attempts before the engine started. The first two times my son noted that the ground didnt produce any spark when it was placed on the battery (Hot was already in place). Each time the vehicle did not respond. The third time after we reset the computer there was spark and sure enough the vehicle started without issue. On Saturday, I spent hours pulling the ECM, TCM and checking connections along with pulling and cleaning all ground points in the engine compartment. There is one block ground underneath that I couldnt get to because the vehicle needs to be in the air to drop the suspension to get a wrench on the bolt.

Has anyone every seen something like this where the vehicle is completely dead then comes back and run without issue? I hopefully eliminated any questions of a ground, but if someone has detail on the ground points they could send me I can verify that I didnt miss any. BTW, the grounds all looked pretty good and I didnt find anything that seemed suspicious to me.

He drove the vehicle Saturday, Sunday and this morning it started without issue. I will keep an eye on it but I am leaning towards the ECM being defective.

Would appreciate any feedback or ideas.

Thanks