I helped a fellow C5 owner last weekend. He had a problem where his IPC would turn off/lose power. If he cycled the key to off then on, it would come back to life. I had him to monitor the voltage on the IPC fuse. Low and behold, when he probed the test port on top of the fuse, the damn IPC came back to life. He removed the fuse and the spade lug was burnt and had solid corrosion on one side of it. The fuse holder terminals were very loose and had very little grip on the fuse lugs. PROBLEM SOLVED!

So,,,,you’re going to need to make sure that all connections in you power supply circuits are making proper male to female connection. Don’t just eye ball it. Use a male pin of the same size and test the grip on the female pins. Look for over heated corroded pins.

I can’t count the number of times that I have seen ****ty Delphi female pins fail. It just plain sucks.

 

Bill,

By checking the power circuits--you mean in the fuse box? Pull fuses and check there? These don't have pins--what connectors would be most suspect? Where is the IPC--I don't even know what it stands for!


The good news is that I finally got some time to pull the green cover off the ignition switch...and YES...the same 2 contacts as in Mark's switch (per your write-up)are discolored. The rest of the metal pieces in there look new--much better than Mark's. I wonder if Mark or a prior owner had keys on the ring as a daily driver? It seems something happened to those contacts (such as road course w/keys on the ring) that wore it out in much less time then it should have taken. These things must be vibration sensitive. It doesn't look like a great design.

So...I still think there is some explanation (other than the ignition switch) for the fact that it took 3 cranks to start it w/ a new ignition switch. But I think the switch was the cause of the issues on track.

Thanks for your help w this...I owe you some Beer!

 

Well--I hear what you're saying...but I really did follow your advice. Remember, my shop's advice was to keep driving/testing the car, re-produce the issue, and get some diagnostic equipment on there to find out what signal was dropping out. Another great mechanic & driver at the track suspected the harness under the torque tube--if he is right, my shop's advice would help confirm that suspicion.

Your explanation about the serial II data was key in pushing me away from that explanation... I owe you some beers!

Anyway...I still thought from your words that it might be the wire TO the switch. So with the little time I had--I chase that down + checked the starter area again.

In terms of changing out the switch--it looked like it would take me several hours since I haven't done one before--plus risk of breakage to the dash pieces. My time is very limited---wife says I have better things to do!!!

So...I figured for $50 for a switch that it'd be easiest to get someone else to change it for me. This way I get a new switch--with costs to go on track even once, it's good piece of mind vs a DIY repair of the switch.

Thanks again!

 

yea, pull the fuses and check the female ends in the box. ipc, insturment panel cluster. my fuse was arcing so much from the bad contact, the ends were almost completely black.