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There is 12 vdc @ yellow wire (C2) in start position.
Car DOES crank jumping red and purple!!
Does that indicate a bad neutral safety switch??
Or TDR relay?
Last edited by TRPLBLKC5; Feb 22, 2022 at 07:02 PM.
So you either have A) bad TDR relay or B) the starter enable relay at the BCM is not grounding that part of the circuit…is the instrument cluster still dead ??…it would be good if you can look and see if you can communicate with the BCM with a scan tool…if no comm that starter enable relay will not function..I’m on my way to my Corvette Club meeting so I won’t be home for awhile !!
To check the TDR take your voltmeter and see if you can probe the yellow wire with your red lead and the black lead to the yellow/black wire…crank the car and see if you read 12 volts on the voltmeter…if you DO the TDR is bad (the load side relay contacts no good !!…if no 12 volts it may be the BCM which we don’t know if we can even communicate with at this time.
TDR. No voltage with yellow wire and yellow / black connected to a voltmeter.
Red lead to yellow. Black lead to black yellow.
What is next?
If you tried starting the car and read no voltage the starter enable relay is not working...you will have to get a scan tool to see if you can communicate with the BCM first...a cheap code reader will not work....with no BCM communication the VATS system probably isn't functioning either and also the BCM and PCM must communicate with one another...the IPC is dead so you can't see the security light anyway...that's all I got !!
Thank you. Suggestions for a scan tool?
Should I replace the BCM? Or is there too many other possibilities?
Is the BCM the first in line with regards to communications?
I greatly appreciate your knowledge and willingness to help me out.
Thank you. Suggestions for a scan tool?
Should I replace the BCM? Or is there too many other possibilities?
Is the BCM the first in line with regards to communications?
I greatly appreciate your knowledge and willingness to help me out.
No problem !!…without seeing what modules you can and can’t communicate you’ll only be guessing…as far as scan tool there are many but a higher end bi directional scan tool like this will run about $1,000 but you can use it on domestic and imports…I have an Autel MS 906 which is touch screen but it’s not Bluetooth…you have to be careful where you buy it because some of these are “gray market” and Autel does not honor these under warranty…I purchased mine directly from an Autel dealer in Long Island, NY…my Snap On Verus Pro is Bluetooth and that is the one I mainly use…that one is a LOT more expensive but it’s got a scope which is just OK but I don’t use it…my Picoscope is laptop based and that is what I use…if you can’t communicate with a module the first thing is to check that modules power and grounds…let me look up the power and grounds for at least the BCM and you can check those.
OK, BCM has 4 powers and 2 grounds...BCM has 3 connectors...top is C2, middle is C1 and the bottom connector is C3.
POWER
C1- A4 (orange wire) hot at all times and power from fuse 25- IP fuse box
C1- D13 (pink wire) hot in on and start...power from fuse 13- IP fuse box
C2- D12 (yellow wire) hot in on and ACC and power from fuse 9- IP fuse box
C3- A4- (orange wire) hot at all times and power from fuse 23- IP fuse box
GROUNDS ---connect test light to battery B+ or one of the powers above and tip of test light to ground
C1- A9 black/white
C3- A2- black
Awesome. I'll find the schematics on other control modules and do the same.
What are the other control modules do I need to check? While I'm contemplating a scan tool.
I did a fair amount of research on C5s before purchase. This issue is no surprise.
I'm retired and this car is a hobby. Maybe more than. I do much of my own work.
Electrical issues are challenging. Again, thank you.
For now I’d check the BCM and then maybe you’ll find a scan tool…without one there is only so much you can do…I’d also invest in a FSM (Factory Service Manual) for your car…these cars are getting old and you WILL have other issues down the road. Many members here struggle with electrical but if you learn the fundamentals it’s not difficult…there are tons of Youtube videos that can be of help…highly recommend Scanner Danner’s YouTube channel if you want to learn this kind of stuff….also my buddy Matt whose a DIY’er and his channel is Schrodingers Box….he’s the one I mentioned who lives near you…TST Seminars is another good channel.
Had no power to C1-A4. Repaired. Starts and numerous other issues repaired.
I had 12 vdc @ both sides of the fuse. No power @ C1-A4. Removed and checked the fuse for continuity. Couldn't find anything wrong.
Very fine sandpaper and a paper clip to attempt cleaning contacts. Replaced fuse. Now there is 12 vdc @ C1-A4.
Last edited by TRPLBLKC5; Feb 27, 2022 at 01:27 PM.
