im going to try and list everything i know about the car. start with i bought it off craigslist guy had it listed as mechanic special think it needs bcm

so ill start with the day i got it, guy had the car put away in a storage unit when i went to go pick it up car fired right up he had the battery disconnected because it was in storage and he said the car with the issues it had would drain a battery. loaded it on the trailer no issues , when i got it home to unload it put the battery cable back on driver door didn't want to open, driver seat wouldn't move and when i went to start the car heard a few dash noises and cluster back light came on but no start. so i went over to the bcm jiggled some wires and pushed on the clips and after a few tries got it to fire up. "seems like when the car is either hot from running or being in the sun it act up"
when the car acts up it does the following gauges drop out fuel volts temp and oil pressure also radio on and off randomly driver seat stops working windows need to be re indexed says service column lock service abs low fuel service fuel and puts up the pad locks and abs light. while all that happens the rpm and speedo still work

so after all that happened i pulled up the carpet got all the grounds and plugs i could find cleaned them and electric greased them same with bcm and battery terminals and the few big plugs right by the battery.

started car up no issues it was a cooler night drove for 2 hours no issues, the next day it was in the 90s went to start the car and same thing first abs light then all the gauges went crazy so i took it to a buddies shop he put his scan tool on it "snap on" and said only had 2 codes old pending charging sytem and clutch peddle switch code p0621 p0833 then i heard the bcm click and it threw 15 codes from the bcm. i turned the car off strted it back up car worked fine again.

most recent thing was tonight car was driving no issues gauges started messing up got a charging system service light and then my car was saying alt was 12.9-13.9 volts was always 14.1

as for whats done to the car long tubes xpipe no cat and corsa extreme mufflers
msd plug wires
new battery last year

not sure what to try next like i said only seems to act up under high heat weather the car is super hot from running or because its a black car and the sun is baking it

 

here's a youtube video of what it does it mostly does it when its hot as hell out. took that video then drove to the gas station shut the car off came back to it issue free

 

No clue but I would start with the easiest fixes first. Have the battery tested. Check the battery connections, my 05 is extremely fussy about the battery terminals being tight. Check the grounds. Check the wiring the best you can at all the connections. On my 05 there is a metal "hoop" attached to the passenger's side head at the firewall that holds a large wire loom. I keep track of it and adjust it from time to time because it is starting to cut through the loom and I worry about the wires being cut. Since you have headers check connections at the starter.

Of course, it could be a faulty BCM but I'd rule out other issues first as they don't go bad that often.

 

ive checked every connection took the interior basically out of the car. Checked the fuse block under the hood cleaned every plug I could get my hands on interior and engine bay and di greased them had the battery and alt load tested. Connections are tight. Only act up when the interior of the car is hot as *****

 

Not to be nit-picky but did you check the connections at the starter? A lot of people with headers have the connections deteriorating at the starter terminals. I don't have headers, but you can still tell the plastic has seen some heat.

I'm guessing here but it sounds like a CANBUS problem which to my non-professional mind says its the battery, the connections, or the BCM ---- but you knew that already. If sounds like you need a diagnostic tool that can show you the BCM communication during the time the problem occurs. (I think at TechII will do this.)

Please keep posting I'm very interested in this problem.

 

i looked over the started the other day with the car having longtubes i didnt really want to have to take them off. both connections were tight and the plastic doesnt look like its turned colors or seen a ton of heat.
battery is a year old and i have had it tested in and out of the car same with alt. ive pulled the bcm out and inspected that as well. only bad connection i found on the entire car was the one under the driver seat for the contols cleaned it up and greased it. some times the car gets so dumb i gotta go thru the hatch to even get into it because the doors dont work at all

 

Update checked the starter all connections good cleaned them anyway and di greased them Put them back together still same issues. Car still does crazy **** and all at once things work then don’t work says service abs tire pressure column lock robs low fuel service fuel all gauges drop out and come back except for rpm and speedo they always work.

 

Other than what appears to be some copper corrosion on the upper part of the connector in the top picture, the BCM boards and your fuse box look great and nearly new. I still have no clue. I think you are at the point of some really deep troubleshooting, throwing parts at it, or letting a good corvette shop look at it.

I still think you should get a recording of your CANBUS traffic and see what's failing first at temperature. (Of course, that's easy for me to say.)

I'm out of ideas. Please post if you find anything.

 

I heard in another thread that someone cleaned the ABS electrical connector and it resolved the issue. Im interested in this also, just found out my dads car is doing the same thing.

 

I ended up having a wire under my driver seat that was shorting out causing all those issues

 

Thank you for posting the solution!!