Darn you Cougar...I was getting ready to go out the door to get a used BCM when I decided to check the forum one more time. I read the forum discussion that you sent a link to and now I can't in good conscience do it. The fact of the matter is I'm better at reading forums and taking gambles than I am at electrical testing. I think I'll go get a multimeter with alegator clips and roll up my sleeves and figure it out. First I have to learn to read those darn wiring diagrams...LOL. Thanks for all your effort on my behalf. You can be sure I'll post the fix for the world to see. Do it yourselfers unite!

TJ

 

I realized this afternoon that my friends instrument cluster from his '01 SE would probably work in my '02 Sport. It worked but it didn't fix the problem. I'll find that needle in the hey stack eventually. At least this attempt to fix it was free and didn't take very long. Stay tuned for next update.

 

Was hoping you didn't get fixated on the BCM though it could very well be the culprit. Be a shame to spend the bucks on a new one or even a sourced BCM and have it not be the problem. As stated, there's a bit more to look at first. You proved the cluster was not the culprit. You're that much closer now.

 

Update: Unhooked HVAC - problem persisted, unhooked radio and "cigarette lighters" - problem persisted. Managed to fry 5 of my bulbs in cluster and 1 in my friends. I'm guessing static discharge did it as I've been sparking all day rubbing on the carpet of that minivan.

My next question: From reading the shop manual it appears that power sliding door modules link to the BCM but I don't have them. All I have is power door locks. Would the power door lock modules take down the PCI BUS? It doesn't appear that they are on the PCI BUS only the Power Slider Module is on the PCI BUS. So can I skip this step or is it possible that something shorting in my door could indirectly crash the PCI BUS?

One little tid bit I discovered today. I was measuring the voltage at pin 2 of the OBD connector today which is the one hooked to the PCI BUS. While I had the volt meter on it my light show happened! Before the light show it was reading around 1.0 volts but was jumping between .88V and 1.25V. I checked my buddy's and his did the same. While my light show was occuring the voltage dropped to about .20V on average. So it I think this confirms that the data bus is crashing.

Other than the Overhead console thingy I'm not sure how much more I can disconnect that's on the PCI BUS and still have the van run. After I do that I may take a stab at that BCM. Can anyone advise on any other modules that are on the PCI BUS that I can unplug and still start the van to test it?

Thanks as always for your help.

 

A couple new clues have arose that I'm hoping will trigure a better understanding of what's malfunctioning in my van. Clue #1 is that the problem has progressed and now my "light show" sometimes continues after I turn off the car. Tonight I had the voltmeter hooked up to the pci bus while this was going on. The voltmeter at one point was actually measuring negative voltage (-.04V). I'm not even sure what that means! I then shut the car off and removed the key. The wipers stayed on as well as many of the lights on the instrument cluster. Does this fact sway any who are reading this towards it being a module rather than a wire in the harness or a connector? Another clue is heat is definately a factor. I can now recreate the symptoms fairly predictably by starting the van, turning on all power accessories and letting it idle for about 10 minutes. The warmer the van gets the more predictable the symptoms are and the symptoms happen for longer periods of time the warmer it is.


I keep hearing that intermittant problems are almost impossible to solve, however I can recreate the symptoms on a regular basis now. Last week I knew very little about electronics...now I'm making my own diagnostic tool to plug into the diagnostic junction port so that I can separate most of the modules on the PCI Bus. I say most because taking the "junction plug" out of the diagnostic junction port separates all of the modules but you can't start the car. I plan on making jumpers from each of the used terminals in the junction port and connecting only the ones needed to make the engine start like the ipm, bcm and ecm. If I still get the "light show" with only those three then I guess it's one of those three in which case I'll be starting with the BCM. If that keeps the "light show" from happening, I'll connect one module at a time to the PCI Bus until I can recreate the "light show". Who needs the $5,000 DRBIII scanner anyways?


I don't know if it will work but the car aint fixing itself out in my garage so I guess I better keep trudging forward...

 

Don't know if you guys have seen this, but I came across across this article on diagnosing Chrysler PCI communications. It makes sense once you read it a couple of times. It mentions the Diagnostic Junction Port

http://www.gearsmagazine.com/view.as...3-eadd826e7991

 

I had a similar problem...At one time the key was removed from ignition and the front and rear wipers would continue to work with no power through ignition. Then I lost all gages and instrument lights. Did a voltage check on cluster harness at the plug and was not reading 12v.
So I traced the wires to the engine compartment fusebox. removed battery and tilted box forward and found corroded wires. One was only holding on by literally one thread. Cleaned all corrosion and remounted wire to clip. Soldered in and re-inserted clip into plug. tested plug and all has been good since...

Hope this helps...

Good Luck and Keep us Posted!!!!

ZJ