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Message: <blockquote data-quote="Will_K" data-source="post: 21411" data-attributes="member: 7902">Hello everybody. A few weeks ago I bought a 2009 Equinox mechanics special. When I went to the dealership who was selling the vehicle wholesale, the sales guy had the car started when I got there and it was overheating. A quick oil cap inspection showed a likely bad head gasket. I got a discount and trailered it home. The intent is to have this car ready for a child's first car on her 16th birthday a month from now.The mechanical part of the engine was no problem. I replaced the head gasket and most everything else that needs replacement on a car with 176k miles while I was in there. I drove the car to work a few days with no issues.The other problem was that the car came with an aftermarket car alarm system, and at the initial test drive it was going off non-stop. That was addressed by unplugging the horn. Removing this system lead to a no crank issue that I haven't figured out.My assumption was something got cut that I couldn't find, so I replaced the dashboard wiring harness, but the same thing still happened. Turning the ignition key to start resulted in cutting off power to everything that gets power when you turn ignition to on. But that's not quite the problem I need to deal with now.For whatever reason, this turns into a case study in why you disconnect the battery negative cable. What I had been doing is disconnecting battery positive because it was more convenient to drive the nut on the battery cable connection to the terminal. What happened next is that whatever I was doing, the ECU managed to come into contact with battery positive while the negative cable was connected. A sound resembling a bottle rocket whistle then pop followed and a small puff of smoke then nothing.Where I'm at, I have no electrical power to anything. No dashboard lights or displays, no dome light when the door opens, nothing.I've checked all the fuses and none are blown, all have continuity. Battery is charged. I can read 12 volts at every fuse with a multimeter to the battery negative. There's continuity to the negative battery terminal from the engine block and body.I've run out of logical explanations to look for, do you have any suggestions? I'd think this was something like a blown fusable link but I can't see anything like that, and if that was the problem it would seem as though I'd have had no continuity to the body or engine.</blockquote>

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