Chrysler Repair: Transmission, dodge grand caravan, bias level

Question
I have a 97 Dodge Grand Caravan ES. The transmission is in limp mode. Using the ignition my check engine light shows code 66, which can be TCM not communicating. I took it to the dealer and they confirmed the TCM is not communicating but the PCM & BCM and everything else is. They said it's a wiring problem on the positive CCD communication wire. It should read below 5 ohm but it reads 43. I've been an electrician/technician for 30 years so I took it home with the troubleshooting block diagram they used. I checked from positive wire from PCM to TCM and got less than 1 ohm, the same with the negative. Also I unplugged from both modules to get a true reading. I took it back to dealer and showed the tech. what readings I got and even showed him with a fluke meter while everything was plugged in. They tried a new VSS, it did'nt fix it then they decided to install a new TCM and it still did'nt fix the problem. They believe there is still a wiring problem since the TCM will not communicate, but it's not th CCD for it still reads good. All I have is a Haynes manual and it does'nt go into detail on the TCM or the input voltages. My question is, does the TCM require a 12 volt input or a lower one and on what pins should I read this input voltage. I figure the only other way it will not communicate is if it lost it's input voltage. Also where can I find a wiring schematic for this TCM on the internet? Showing all inputs and outputs. Your input would be greatly appreciated. Thank You.

Answer
Hi Lester,
Any thing positive come from my earlier reply? If not, let me mention that I do have the '94 Chrysler manual on the CCD bus system. Do you happen to know whether they got a bus-specific fault code? If so, I can tell you what to do about that code. Among the possibilities are:
Not receiving bus messages correctly
Bus bias level or bus (+/-) open
No termination
Shorts or opens of various kinds
No bus bias
Bias too high or too low.
So see if you can get a fault code like anyone of those.
Roland




Hi Lester,
Sorry to be a little slow in replying, I was tied up during the day. I have the 41TE trans wiring diagrams in a '96 Cirrus/Stratus Chrysler shop manual and let me share the power supply wire colors now. I can tell you a bit more later this evening when I write again. It looks like there are 3 12V supplies.
A24  circuit is direct from the battery pink/yellow wire on pin 56 of the 60-way; it also powers the trans control relay.
A41 supplies power thru the ignition switch but only in the start position and should appear on pin 8 yellow/orange. It is tied into the park/neutral safety switch.
F11 supplies power on pin 11 red/yellow in the off, start, and run position of the ignition switch.
I can tell you more about the data link, etc. connectors and see if I can find anything else. I would be glad to xerox and mail these pages to you if you will tell me a mailing address.
I'll write again later today. Let me know if you have other questions based on the above.
Roland