electrical issue? Car shuts down difficult starts - dash light flicker

[reeferdale]

Decided to join the C5 club so I traded my mint C4 vert in for a 99 vert last month (Automatic). Went out last week and car was dead not even a click. I did not even notice if the lights were on the dash. Tried to jump and would still not even turn or click. Charged battery re-installed and fired right up, drove for 1 day no problem. Came out of a store and car cranked fine just hard time firing up - had to pump pedal and hold to floor finally started and drove normal. Next day drove to work no issues, came out of work and same starting issue, had to crank car 5 - 6 time before start. was driving along at 50mpgh and car just shut down, gauges just dumped to the left and no engine. threw it in neutral and it started right up and drove home no issues. Pulled codes - lot of 1016 loss of PCM communication on all modules, these could have been old codes. Cleared all codes and was afraid to drive to work Thursday. Got in Thursday night and test started right up 2x. Friday morning, hard start and cut out on way down the driveway - checked codes only 2 this time IPC 0516 - Speedo circuit malfunction and IPC 1016 along with a RFA 1016?
I checked the battery terminals, they are tight and I cannot see any loose wires or connectors. I am thinking now that the original issue was probably not a dead batteyr but this same issue.

I notice that when I put the key in, the instrument panel lights will flicker rapidly and I will get the no start, hard start condition. If I remove the key and try a couple times I will finally get a clean key insert and normal instrument lighting and the car fires right up. I just ordered the FSM for 1999 C5 but wondering if any experts out there have any ideas for me? I am thinking I may have a short somewhere - but where! I also noticed that a couple times when I turned the key, I got a hard 'clunk' from what I assume was the starter. This only happened 2x and may just be because of an intermittent electrical surge?

thanks for any idea or advice

[Hib Halverson]

I'm going to guess this is a wiring and connections issue.

Since you have the FSM coming, when you get it, read the section on electrical, find all the chassis grounds and check their tightness.

Check the connections at the PCM which under the battery.

You might find a problem with the PCM or harness due to a leaking battery.

[reeferdale]

I'm going to guess this is a wiring and connections issue.

Since you have the FSM coming, when you get it, read the section on electrical, find all the chassis grounds and check their tightness.

Check the connections at the PCM which under the battery.

You might find a problem with the PCM or harness due to a leaking battery.

Yeah, I sort of figured that also. There is no sign of any battery leaking, the entire engine compartment is very clean. I started to look at the fuse connector block under the hhod and was going to pull it, it looks like besides the top cover, the entire body will 'unplug' from the lower section, but, until I get the FSM I don' t want to start pulling stuff aprt that is not meant to come apart. I think it is a short or ground issue also, when it happens, there is nothing, or just enough to clik the starter, but when the problem does not present itself, the bettry cranks like new and the car fires right up with just a touch of the key. My thought also is to check all ground bolts to start - I think this is going to be one of those PITA problems that is going to take part following instructions and part luck to resolve - thanks

[LLC5]

Yeah, I sort of figured that also. There is no sign of any battery leaking, the entire engine compartment is very clean. I started to look at the fuse connector block under the hhod and was going to pull it, it looks like besides the top cover, the entire body will 'unplug' from the lower section, but, until I get the FSM I don' t want to start pulling stuff aprt that is not meant to come apart. I think it is a short or ground issue also, when it happens, there is nothing, or just enough to clik the starter, but when the problem does not present itself, the bettry cranks like new and the car fires right up with just a touch of the key. My thought also is to check all ground bolts to start - I think this is going to be one of those PITA problems that is going to take part following instructions and part luck to resolve - thanks

Make sure that it's not the electrical part of the ignition switch by slowly turning the key left to right, and checking if to see you lose dash indicator lights and accessories with any small movement of the key. Good luck with it.

[reeferdale]

Hi all, I have torqued the battery leads and checked the body grounds. I have
been driving the car for the past week or so and I have a definite repeatable
set of circumstances that I can now share. I notice that when I insert the key
and turn it to 'ON', there are times that the securtiy light flases rapidly, the
IP lights flicker, the message line that says 'Corvette' will have garbled
letters, and I have a light clicking under the passenger foot panel. I have
narrowed down the issue to this exact series of events every time. If I remove
the key and try again, I can get the issue to go away, but some times it takes
several attempts. A few times I have wiped the key before trying again but I
have also been sucessfull without wiping the key so wiping the key off is not
actually required. I have verified that this issue occurs with both keys.
If I attempt to start the car with this occuring, I just get a click from the
starter like you would get if you had a dead battery, but the car will not
start. I have also had 2 more incidents of the car dying on me while driving and
I have had to remove the key and go through this procedure. Fortunatley each
time the car has re-started and run fine. I now have my FSM, but, before I go
tearing into random electrical diagnostics, I am just wondering what any of the
more experienced members might suggest as a starting point.

Also, I have
no new codes to report. Since this occurs before engine start, I am not sure
that any codes would be captured?
I am thinking I should start with
eliminating the ignition switch as a problem?

Any one have any other
suggestions for a good starting point(s)?

thanks