NotVincent

It's been a long time since I have been in here. I hope some of the bright guys who used to be here are still around and can help me out.

About two weeks ago, I had my 427 out all day, came home and parked it in the garage with no issues. Monday I tried to start it and it was stone dead. I metered the battery and it read 0V. I tried to jump it and even let it sit attached to the jump car for nearly an hour. First attempt to start, it just clicked. Second or third attempt it clicked again but wouldn't stop even with me turning the ignition switch off. The last attempt, I noticed that the car was stuck in accessory mode and the theft indicator on the dash was steady on. The car wouldn't start and I couldn't turn it off. I had to disconnect the battery.

The next morning, I got a new car battery assuming that would solve the issue. It didn't. The car is still stuck in accessory mode and won't start nor shut off. I have tried both FOBs with fresh batteries both on me and in the FOB holder in the glovebox. Still the same.

I found an old post here where someone had a similar issue and resolved it by removing the fuse for the ECM (56), disconnecting the battery, wait 15 minutes, reconnect battery, reinstall fuse. Still nothing.

I tried an OBD2 reader to pick up any codes but there were none stored.

The last mechanic I spoke to had no idea and had a call in to a Corvette expert but that was 2 days ago and he still has no answer.

I have searched and searched for anyone with a similar issue and haven't found anything that has helped. I am hoping someone here can offer a suggestion before I end up having to flatbed the car to a dealer and then be stuck at their mercy for whatever they come up with. Thanks in advance for any help!

helga203

Get the battery checked.

NotVincent

Thanks, but I already installed a brand new battery that I measured at 12.9 V and the issue remains the same.

helga203

If u have a dvm' check amp draw. Do u know how to do that?? Just put dvm wires in in series with the negative .Battery to volt meter in. Out to ground cable . Yes disconnect negative.

NotVincent

Although that would be a good idea if the car attempted to start, since the car is stuck in accessory mode and the start switch does absolutely nothing, I don't see how that measurement would reveal anything. Thank you for helping though.

helga203

Has nothing to with starting. Put the dvm in series then let the car go into sleep mode and check what the draw is. make sure ur battery is fully chared.

JasonAndrew

Do the lights and radio work? It still clicks or not? Clicking is a dead battery, voltage or not.
IM not sure if you did this, try pushing the starter switch and holding it on OFF to shut down the car. Then make sure the car turns off? Then holding the starter switch for 2 seconds to start.

87SAM

Automatic or manual?

NotVincent

I am not sure what you mean by "sleep mode" but when the battery is connected, the car stays in accessory mode with the nav screen on, accessory mode displayed above the steering wheel and the security indicator icon on. I can turn off the nav screen but the only way to turn off the dash indicators is to disconnect the battery. I would therefore expect the current draw to be unchanged regardless of any start button actuations. However, if you are assuming a fault in the electrical system that may provide enough base current to operate all devices but not enough current to turn it over, that may be something to investigate. I will take a reading in a bit. Thanks.

Everything works fine as it should in accessory mode. All windows work, door locks work, wipers work, radio and nav works, all lights work, even AC fan works. There is no clicking when attempting a start. the start switch does absolutely nothing in any position, with either short presses or holding it in. It just constantly has the orange LED on that will not change regardless of start switch position. Thanks.

NotVincent

Manual. The only way 427s came. And I haver tried starting it in Reverse and every other gear and even jiggling the shifter but no luck. Thanks.

grinder11

2013 427 60th Anniversary model convertibles were available with an Auto trans. You might want to PM C5 Diag, or Bill Curlee, and explain the situation. Maybe the ignition switch, or starter went out, or??? Best of luck to you, and please keep us posted....

NotVincent

Just tried this. With the car at rest in accessory mode, it is drawing about 6.5A. When attempting to start, the draw goes to 12A. I am not sure how much of that start draw is from the brake lights being on during the start procedure or any processes related to the clutch depressed though. Regardless, the start switch still remains lit in orange and didn't change.

chevyjeff

start chasing wires looking for a short by starter or bad solenoid connection.

then start checking every ground connection. starting w/ motor, then to body

check w ohm meter the alt wire to the starter w battery disconnected.
the factory gauge wire is too small. look for loss.

check all the connections to ecm, bcm
.look for corrsion and make sure pins are fully seated, apply dialectic grease
id also check every fuse and relay for connectivity under hood

its been my experience with gm cars that electrical gremlins like this are usually a bad ground.
or that some harness has rubbed or got burnt and shorted out.

be methodical and patient.

been there done that. spent 12 hrs. once chasing short on ficm harness on 2004.5 duramax...lol

87SAM

Isn’t the ECM fuse 11 in the under hood fuse block?

NotVincent

According to the layout located on the cover of my underhood fuse box, 11 is the ABS. 56 is for the ECM/TCM/EASY KEY.

87SAM

Yep, I was taking someone else’s word on it in another thread. Checked mine, and you are correct.

Got it from this thread:
https://www.corvetteforum.com/forums...sory-mode.html

NotVincent

That is the thread I found via a search and I tried what the OP said and had no luck. Perhaps I should try it with Fuse 11? I have seen stranger things happen with my car when it had a wheel sensor failure.

NotVincent

UPDATE - Problem Resolved!

Mechanic tells me that he was able to start the car by simply replacing the battery in the FOB. I find that hard to believe since I put fresh batteries in both FOBs and neither worked. However, he wanted to keep it a day or so to determine what caused the battery draw since he found the battery dead the next morning. Fortunately, they keep cameras on inside their garage and they saw that the car attempted to turn on by itself at 2:30 AM. They keep the keys with the cars but since there was no brake pedal nor clutch depressed, it just turned on to accessory mode and drained the battery. He traced the problem to a faulty start switch. Weirdest thing I have ever heard of.