Hi Frank, thanks for responding. I have a 2001 GC Limited 4WD with the 4.7L V8 and Quadradrive.
When it first wouldn't start I checked the battery and terminals, all of the fuses under the dash and under the hood, exchaging any that said anything about ignition or starting, swapped the relay with the wiper relay, the wipers worked both before and after the swap.
The starter is good, if I jump the relay sockets terminals 30 to 87 the starter works, that is how I have been starting it. I noticed that it usually will start on its own first thing in the early morning when going to work after the car sits all night, but usually won't start after that, even after a short drive of only a coulple of blocks. When I come out after work, it usually won't start even after sitting 8 to 10 hours, but the ambient temperature is 85 to 95 degress right now here in Southern California, so it seems to be temperature sensitive.
Today after work I checked the relay terminals with a DMM, with the following results:
Battery voltage with key off is 12.52V, with key on is 12.41V
With key on: 30 to ground is 12.38V, 87 to ground is 0V, 85 to ground is 11.43V, and 86 to ground is 0V.
With key in start position: 86 to ground is 12.41V
With key off: 30 to ground was 12.66V, 85 to ground is 0V, 86 to ground is 0V, 86 to battery positive is 12.62V, 87 to ground is 0V, 87 to ground shows continuity (0 ohms), 86 to ground shows open (Infinity ohms), 85 to ground shows 0.43 ohms, 30 to grouns shows 1.45 ohms
It was showing a code of P1698 (No communication from TCM to PCM) for awhile, then it cleared, then it showed up again, then it also showed a code of P1899 (P/N switch stuck in park or gear). So I think the problem is in the transmission range sensor, since I can't find a typical park/nuetral switch on the side of the trans. How do I check the TRS, and how do I change it if needed, is it a seperate part or do I need to change the solenoid assembly.
Sorry for the long post, but I wanted to be as detailed as posible to make it easier to help diagnose the problem. Thanks for your help.