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Maybe I can get by tomorrow. I have an appointment at 10 AM, but free after that.
I'll email you, if you want to provide that, after my appointment to see if it a good time for you.
Ya know, You have a built in DTC reading system in your IPC. Anyone that has any issues with their C5 should know how to read their DTCs right from the driver's seat anytime that they want without using a scanner.
IMPORTANT INFORMATION: When you experience a C5 issue, pull over safely and WITHOUT TURNING OFF THE IGNITION, clear any warning messages in the DIC by pressing and holding the RESET button until that message or all the messages clear. Once all the messages are clear from the DIC, go into the DTC reading routine and see what the car is complaining about. Some DTCs clear or reset or go to history when you turn the ignition off and back ON.
There are a few reasons that your C5 will just die/stop running/shut off. If its security related or Column Lock related, you will normally see a DTC related to the issue.
However, If its an IGNITION SWITCH related problem, just like turning the engine OFF with the key on purpose, ZERO DTCs will be set.
I have seen dozens of bad ignition switches. A bad ignition switch due to arced contacts or other mechanical/electrical failures inside the switch normally cause specific things inside the cab to stop working or work abnormally. Dirty, arced or defective switch contacts will frequently cause the switch to output a lower voltage that the 12 VDC battery voltage that the car needs to operate as designed. Low switch voltage does some crazy stuff. I have seen ignition powered circuits (circuit fuses) read as low as 5-7 VDC when the switch contacts are defective.
That being said I have discovered that more times than I would like to admit, one of the most common failures of the ignition switch is the two harness CONNECTORS that connect to the ignition switch. The female pins inside the harness connectors (especially the large pins in the connector) spread apart and make a very poor connection with the male pins inside the switch connector. The slightest vibration or temperature change can cause the switch to lose ignition switch power and shut down the engine/car. Other than being very observant and knowing what they should look like, determining if the female pins are spread apart and causing an intermittent or poor connection is to do a PIN-PUSH-PULL TEST. That involves finding a male pin the same width and thickness as the male pin in the switch connector and inserting it into and retracting it from the female pin inside the car harness side of the connector. The male pin should have a very distinct and noticeable DRAG or resistance to inserting and removing the male pin. If it's very loose and or has minimal drag, the female pin is spread and making a POOR CONNECTION!
I have in the past been able to manipulate the two connectors and either reproduce failure or cause the ignition to come back from a failure condition ON or shut OFF by wiggling and twisting the switch connectors. I have seen a couple female pin connections so bad that the female pin got so hot that it melted the connector cavity for that pin.
RECAP: READ YOUR DTCs and see if any are set. A DTC with a "C" suffix means that the problem is CURRENTLY happening. DTCs with a "H" means that it happened but is NOT currently happening. Always include the H or C suffix when posting DTCs. If no DTCs are set, check the ignition switch connectors for damage/bad female pins, corrosion, or wire damage. Normally, a security issue, VATS issue or column lock issue will set a DTC/s.
swpitman C5 DIAG is an EXTREAMLY GOOD TROUBLESHOOTER AND MECHANIC. Second to none! If he is inviting you to his garage and offering to help you, Ide be there yesterday! Just my advice and opinion.
I'm on my third ignition switch.
Original one was replaced on a re-call for not unlocking the steering column.
Second one would sometimes not start/crank over the car.
The one in there now was installed by an incompetent mechanic who was about 70 years old. Took him 3 hours to install. They handed me back the keys and said my car was outside. Hopped in the car and the switch was installed so crooked that I couldn't even get the key in it. Went inside and told the owner, he went out and couldn't get the key in either. He reached under the dash and took about 3 minutes to straighten it out so that the switch was in line with the hole in the dash.
An ignition switch can be quickly diagnosed by doing a voltage drop check between battery positive through the ignition switch to any of the 4 power wires that feed the various circuits in the car.
I've seen and fixed many different burnt contact ignition switching over the decades. Always always the primary contributing ingredient in lock cylinder switching is due to low voltage and voltage loss, which raises current flow through tiny contact patch area causing damage you see.
The higher the voltage at the time of contact, the less current, sparking, and deterioration the patch will assume.
This is generally due to small ignition cylinder wires, and or insufficient relay handling for the starter solenoid. Some vehicles like the nissan 240sx don't even have a relay between the lock cylinder contact patch and starter solenoid, that car is where I first began to notice the extreme burning of the contact patch due to high current.
In the C5 diagram I see now, I recommend as preventative maintenance to replace the highlighted wires and relay to a larger diameter and more robust relay to prevent voltage drop during cranking from causing a large sparking effort at the contact cylinder patch area.
I circled key area of interest.
First, notice the C8 coming off a 60Amp fuse appears to me to be powering the solenoid relay. The wire here could be upgraded, especially if age has it deteriorated for any of these as a matter of course.
Next notice after the relay, there appear to be multiple junction points which are unwanted.
In other words, what you want in a high performance vehicle starting is a direct single large diameter wire from that starter solenoid relay (labelled as 'theft deterrent relay') directly attached to the starter solenoid. Every junction A2, C2, C1, is a voltage loss or drop, along with any aged/aging wiring and corrosion between junctions and so forth additionally.
What I traditionally do is add my own high performance relay as shown, and you can measure the voltage difference across the relay you currently use to see how bad it is if you can record it in real time during cranking such as with a logger or simply analog measurement and a camera as I have done frequently.
In the case of C5 I would use the existing 'theft deterrent relay' to simply activate my new high performance relay so it stays functional with the Park/Neutral switching as if nothing has been changed at all, but this way current can flow through larger wires and directly to the starter solenoid. It has been quite a noticeable difference in a large variety of vehicles.
I completely agree with you, see where you are going and how that would significantly improve what GM gave us, HOWEVER, for the most part, when most Corvette/ vehicle owners see, schematics, have to deal with electrical theory and are tasked with meter operation, that stuff causes them to break out in hives an may have well been written in hieroglyphics.
For the 90% of Corvette owners, properly working OEM wiring and what GM gave us is satisfactory.
I rather enjoy taking someone that is petrified of vehicle electronics and allowing them to understand the schematics, theory and operation of the circuits.
Our current aftermarket Ignition Switches are made overseas and are subpar to the old OEM new ignition switches of past years.
I completely agree with you, see where you are going and how that would significantly improve what GM gave us, HOWEVER, for the most part, when most Corvette/ vehicle owners see, schematics, have to deal with electrical theory and are tasked with meter operation, that stuff causes them to break out in hives an may have well been written in hieroglyphics.
For the 90% of Corvette owners, properly working OEM wiring and what GM gave us is satisfactory.
I rather enjoy taking someone that is petrified of vehicle electronics and allowing them to understand the schematics, theory and operation of the circuits.
Our current aftermarket Ignition Switches are made overseas and are subpar to the old OEM new ignition switches of past years.
Well, for some people owning a corvette is also about modifying. Not everybody will keep 100% original.
And not all factory parts are up to the challenge of 20+ years, or after 20 years, sometimes they need help.
Those are the weak links in the chain, if somebody dare modify them to be stronger.
More to the point, if an engines been restored with a performance compression ratio, or when theres been some battery/wires related distress(weak charging system, oxidized grounds, decades of corrision, etc...) , there are weak links that should be addressed anyways, as keeping a 100% factory ignition circuit may no longer be reliable under those conditions, even if its brand new... especially a fresh engines with some squeeze
I understand a process of restoration intends to keep original intact but if you could do something along the way to help it last and perform well, its just wires and a relay after all, not exactly a difficult or complicated to run a single wire from the solenoid through a better relay. And it can really make a noticeable difference in the cranking ability of an engine. you might not believe how much
I've seen and fixed many different burnt contact ignition switching over the decades. Always always the primary contributing ingredient in lock cylinder switching is due to low voltage and voltage loss, which raises current flow through tiny contact patch area causing damage you see.
The higher the voltage at the time of contact, the less current, sparking, and deterioration the patch will assume.
This is generally due to small ignition cylinder wires, and or insufficient relay handling for the starter solenoid. Some vehicles like the nissan 240sx don't even have a relay between the lock cylinder contact patch and starter solenoid, that car is where I first began to notice the extreme burning of the contact patch due to high current.
In the C5 diagram I see now, I recommend as preventative maintenance to replace the highlighted wires and relay to a larger diameter and more robust relay to prevent voltage drop during cranking from causing a large sparking effort at the contact cylinder patch area.
I circled key area of interest.
First, notice the C8 coming off a 60Amp fuse appears to me to be powering the solenoid relay. The wire here could be upgraded, especially if age has it deteriorated for any of these as a matter of course.
Next notice after the relay, there appear to be multiple junction points which are unwanted.
In other words, what you want in a high performance vehicle starting is a direct single large diameter wire from that starter solenoid relay (labelled as 'theft deterrent relay') directly attached to the starter solenoid. Every junction A2, C2, C1, is a voltage loss or drop, along with any aged/aging wiring and corrosion between junctions and so forth additionally.
What I traditionally do is add my own high performance relay as shown, and you can measure the voltage difference across the relay you currently use to see how bad it is if you can record it in real time during cranking such as with a logger or simply analog measurement and a camera as I have done frequently.
In the case of C5 I would use the existing 'theft deterrent relay' to simply activate my new high performance relay so it stays functional with the Park/Neutral switching as if nothing has been changed at all, but this way current can flow through larger wires and directly to the starter solenoid. It has been quite a noticeable difference in a large variety of vehicles.
The "lock cylinder" is different than the actual "ignition switch". The lock cylinder reads the key resistance for the BCM, the ignition switch handles the 12v path. Two completely different parts.
OP dropped by this morning to have me look at his car...first thing as I always do is check the battery with the Topdon BT600 and his Optima Red Top was "marginal"...OCV test was 12.56 volts when he arrived...also performed a charging system test and his voltage drop on the positive side was 0.2 volts and 0.1 on the negative...complaint was there is a parasitic drain so I recommend a parasitic drain test as soon as the battery is changed...performed a voltage drop test on the ignition switch and all 4 power feed circuits had no more than a 0.2 volt drop in each...a complete code scan in all modules was done and no history or current DTC's in the PCM or BCM...and remember...."TEST DON'T GUESS" !!
The "lock cylinder" is different than the actual "ignition switch". The lock cylinder reads the key resistance for the BCM, the ignition switch handles the 12v path. Two completely different parts.
Ah yes, a lock cylinder, is clearly labelled as a lock cylinder, not an ignition switch.
I did not mean to confuse you, or make it seem confusing, it is merely an artifact of conceptualizing the problem that lock cylinder ignition face frequently.
What we must understand from taking apart and inspecting these items, generally, these sort of electronics burning/contact patch problems originate from a lock cylinder as the instigating source over time.
I am glad you may be confused by this notion because it identifies a sparsely worded interpretation on my part, and so I will gladly add a full description of the problem to include the lock cylinder's mechanical nature as a primary source contributing to the problem of ign switch burning.
First we must remember that not all ignition systems utilize a lock cylinder or key rotational element, and that there are many variations, some more robust than others.
There are many forms of ignition switches, everything from a push-start button ECU controlled, consider modern solid state electronics, to a single wire on a starter push button, funny how they came full circle back to a button that we escaped at some point by implementing the key rotation.
Classically, a key rotation is a mechanical element involving force and torque, some element rotates making contact between two points.
It is these two points that typically burn, deform, melt, due to high current flow through too-small of a contact patch area, in a key rotational style of ignition.
The actual problem with a key rotational is generally not that the engineers undersized or mis-aligned contact patches, although those can contribute especially due to wear over time, they are not the primary source of the gradual, accumulation towards failure in the myriad ignition systems I've dealt with.
It is actually(generally) the physical rotational element of a lock cylinder, being turned too slowly, too gently, and or being subject to bending forces, as when the driver pulls up or down on the key during a rotation torque, which causes the contact patch to begin burning and experiencing high current flow through too-small an area.
This happens because, electricity can flow when only a very very tiny mode of contact is appreciated, imagine turning the lock cylinder incredibly slowly, turn it over the course of an hour, at some point two internal elements which carry current will be just barely close enough to make a connection, and this would undoubtedly lead to rapid heating, burning, melting, because of such an incredibly small point of contact they produced because of such a slow rotation.
In other words, the more slowly the key is being turned, the more slowly the two contact patches approach each other, the smaller area that current has to flow through, the more heat and melting will occur.
This also applies to mis-alignment due to wear, and unwanted up/down bending forces on a key, over time the lock cylinder may 'wiggle' and produce a great contact when being bent only a specific direction. One of my previous cars for example nobody else can start it using the key because the key has to be slightly bent a specific way to engage the internal rotational elements with the ignition switch to get contact. Presumably due to age, wear, whatever. They are all different and their owners partake various habits which can damage and wear more than just the ignition switch itself, which may be perfectly fine in some cases, at least initially, only having issues with the rotational of some lock cylinder elements which gradually leads to the ign burning affects.
To make matters worse, is low voltage supply to the ignition switch, which causes higher current to flow than necessary through too-small of an initial contact patch during a key rotation of lock cylinder. Speeding up the rotation helps with spreading out the heat but the heat is still higher than it should be and can still melt parts generally alot of plastic in that area.
To prevent these issues, we have some general guidelines for lock cylinder use, ignitions which require key turning anyways,
A. Turn the cylinder ignition firmly, quickly, to minimize current flowing through too-small contact patch area inside the ignition switch
B. Do not bend the key while turning unless necessary due to wear/age
C. Maintain high voltage during cranking by keeping the battery full and upgrading wires/relays as needed to prevent voltage drop
I hope you see now why I conceptualize this problem as primarily an key rotational or lock cylinder issue and not directly blaming the ignition switch which seems to function fine in myriad vehicles while others of the same make model year seem to have some issues because of how owners have been using/treating the rotational elements of lock cylinder and maintenance / inspection of voltage-current system.
Cleaning the contacts is treating the symptoms of a problem, but does not the source of the problem.
Bending contacts, changing spring forces, assisting and correcting the applied force & mechanical leverage of the lock cylinder on parts, is all what actually treats some of the problem.
The rest of the problem is, high current during cranking and voltage drop in the starter solenoid wiring and thereby contact area of ign switch, exacerbated by lock cylinder habit & frequency of use.
It is simply stated: Contact current flow occurs at a differentiable, infinitesimally defined area whenever lock cylinder is mechanically deformed some way in key-ignition systems sufficiently, the extent & rate of contact being mechanically dependent variable in all key ignition systems.
sometimes it takes 15 or 25 years to develop an issue after a cleaning and reset, when drivetrain is maintained as original, so why bother mention this?
When vehicles begin start modifying the engine and starting configs this becomes a large issue for alot of vehicles, I frequently diagnose in myriad apps ign switch related
and particularly since the corvette is performance and modification oriented it seems more pertinent than usual so I thought I would point out the relationships between mechanical and electrical, it is my job
Just my advice and opinion.
