Would like to know who on this forum is the electrical guru?? I've got an issue I've been battling for months and has steadily gotten worse over time. It's now at the point that every time I go to start my 04 Z06 the dash lights come on but nothing else works, no door chime, windows don't operate, trunk release doesn't operate and when I turn key to start....nothing. Most of the time I can turn the key off a time or two and everything starts working as it should, fires up and runs great. sometimes I have to disconnect the battery before I can get everything working and the car to start. No check engine light, new battery, new ignition switch, grounds checked. It is autoswapped and the ECM was changed to the older model, from a 2002 I believe, for HP Tuners purposes. Any hints or pointers would be greatly appreciated. Also, if you know someone on this forum who knows the electrical system inside out that would likely be helpful. This has been going on and steadily getting worse for about 8 months, concerned it might leave me walking one day.

 

Check out C5Diag, or Bill Curlee......

 

Seems like you have addressed everything, I would check the B+ connections at the underwood fuse box, and the B+ connection at the interior fuse block. It could still be the Ignition switch, did you buy OEM or aftermarket?

 

dont forget mmartinez.

 

OEM switch.

 

Hi !!…sorry to hear you’re having electrical issues…has this issue started after your PCM change???…I’m not an “electrical” guru but just a plain old guru of the DIY’er kind…LOL !!…normally with a serial data bus issue you will have a car that will start and stall or may not start at all…you will see your fuel gauge go to E, your water temp maxes out, all the DIC warnings scroll through, and your power windows don’t work…all this happening while the fault is active…what happens is all of the cars modules “talk” to each other on a single wire which are wired to each other and the modules are connected in what we call a star configuration…it is called the GM class 2 data network…now how much do you know about electrical ??…do you know how to use a DVOM ??…if you have some skills we can give you some instruction…first thing is scan for codes…with a serial data network issue you will be a bunch of U codes which are communication codes…also if you have a scan tool you will not be able to communicate with any modules…scan tool will show “can not communicate with vehicle”…what happens that if a module loses a power or ground that power or ground will “back feed” onto that serial data wire and all hell breaks loose…for instance the BCM must talk to the PCM and if it can’t the car won’t start…you will either see 12 volts or ground on that data wire…with a scope you will see a 0-7 volt square wave which is a VERY fast signal…the best you can see is the DVOM dancing around close to a volt…I personally use a scope and a CAN test box to check that signal…there are 2 “Star Connectors” that are located near the BCM where all these module comm wires come together…there is a connector which is located inside the rubber accordion boot between the drivers door and door pillar…being that the door is opened and closed many times we find many of these comm issues here…bad connections or oxidation/vertigris…a bad module or it’s power or ground is a cause…video enclosed so you can see what an electrical guru would do to diagnose this issue…Keith is an electrical guru !!…well, do I past the “inside/out” test ??…if you have the capabilities to diagnose this yourself we can guide you !!…last thing…if you do need to take it to a diag shop I can recommend Bernie Thompson at Automotive Test Solutions” (ATS) in Albuquerque…he is one of the country’s top automotive instructors and diagnosticians !!…this guy know his stuff but probably not cheap !!..I’ll include one of his videos too !!

 

, there is also GCG (Gilbert, who hasn't posted in quite awhile)......