Chrysler Repair: ECM/PCM melted down; any circuit problems to concern me?, pin plugs, way over my head

Question
QUESTION: Mr. Finston,

I see you are maxed out, thought this might be an easy question.

I have a 3.3L town & country.  It ran rough, then began not starting until about the 3rd try.  I just had the fuel pump replaced ($500 wow!).  The van ran great for several days.  Then it would not crank (engine would turn over but not run).  I tried to crank several times in a row and started getting a lot of bad smelling smoke from under hood.  Turns out the ECM melted down.  I am afraid if I just buy a new ECM and install, then it will melt down too.  Any thoughts?



Thanks,

Gary


ANSWER: Hi Gary,
I wouldn't believe there is too much risk of that failure. The vast majority of inputs and outputs to the plugs are low current signals and "drivers" (grounds) which won't tax the internals to the point of melting down. There are only two voltage supplies, an 8 volt and a 5 volt on pins 44 and 61 of the gray plug*. You could verify that there was a low but finite resistance on those wires of the plug which would prove that the power supply will not be overdrawn by a short. If you find a dead short to ground then you should look for the reason before plugging in a replacement PCM.
Roland
*You didn't state the year, but these are for the post-'95 controller with two 40-pin plugs. If you have the single 60-pin plug then look at pins 6 and 7.

---------- FOLLOW-UP ----------

QUESTION: It's a 1992, so I will check pins 6 & 7.  Not to sound dumb, but, I need a diagram to know which pins are 6 & 7. Right?  Also, will the ECM need to be programed or do I just connect and go?  Honestly, I'm thinking I am in way over my head here.

Thanks,
Gary

Answer
If you hold the plug with the terminals facing you, the short tab on top, the #1 pin is the top-left one, and you go from left to right to count. The wires in question are violet/white and an orange. I believe that if you get an ECM from a '92 which was coupled to a 3.3L engine and the same transmission you probably won't have to have it programed. But the VIN might need to be put in. That re-programing need came on more in the mid-90's. So try and find one from a wreck would be my advice. To check the circuit measure the resistance between each of those pins and the - post of the battery. As long as you have a digital ohmmeter and have it zeroed when you touch the leads together, then any reading of more than 0 ohms will suffice, say at least 1 ohm.  
Roland