Electrical gremlins: '01 t & c

QuestionEdit

QUESTION: Good Morning:

I own a 2001 Town & Country Limited. I love my little van, but it seems to be haunted.

Problems: During rain, the front windshield wipers won't turn off UNLESS I remove power to the system, wait about 20 minutes, and then reapply power. Then I have to CAREFULLY close all doors and the hood. A hard jarring of the van will turn them back on.

Also, during rain, the rear windshield wiper will stop working. When this happens, the power light will be dim, rather than it's usual bright amber.

The radio will occasionally "reboot". It seems to be jarring related, but it will do it sometimes when the car is sitting still and untouched.

The rear power lift door will sometimes not close on it's own.

The passenger side power sliding door will sometimes not close or open on it's own. It's random.

The battery light will occasionally come on when the van is started. Turning the van off, then back on will cause it to turn off.

The A/C no longer blows cold air. I can hear the compressor click on, but it's all hot.

What I've done: I've checked all fuses. Pulled them and reseated them. Had the software in the BCM updated to the latest version.

Where I'm at: I'm not sure what to do next. I'm thinking that a lot of this sounds like the IPM, but I'm not sure. I'm almost convinced it may be multiple problems, but I'm not sure. I don't know enough about the systems on this van to say for sure and I'd love any advice you care to give. Thank you, in advance, for simply reading this wall of text. It's appreciated!

ANSWER: Let me study the wiring diagrams and get back shortly.

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

QUESTION: No problem. I also forgot to mention that I asked the dealer to pull all codes off the BCM prior to flashing the BCM. They said there were no trouble codes.

ANSWER: Thanks for the added info, see my response to your first question. One possible plug interface that would be worth opening up is that on front of the intergrated power module box which is the plug for the front control module which deals with a huge number of circuits. It might be that there is some water/corrosion/dirt between the pins and sockets of one or more of those interconnections. So spray the pins and the sockets with electronic circuit cleaner, let it evaporate and then reassemble. I don't see a possible issue with the ignition switch by the way as it is not subdivided sufficiently to just impact the systems you are having trouble with. Thanks for the ratings and nominations.

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

QUESTION: I pulled the FCM and cleaned the receptacle on the FCM itself and the IPM. I also cleaned all of the connectors at the bottom of the IPM.

A/C: No joy. Radio: No joy. Power sliding/lift doors: No joy. Battery light: Unknown. Wipers: Unknown.

AnswerEdit

Hi Steve, In answer to the first of your questions I suggested the following: "I looked into the wiring diagrams and don't see a common cause for the variety of issues that you describe that would involve the integrated power module. It might involve the body control module or the power supplies thereto, but even here there is no clear common cause. On the other hand, the issue doesn't seem to affect a great number of systems, nonetheless to be sure I would suggest that you check the clamps at the battery, specifically notice the three wires on the + post clamp to verify that corrosion hasn't impacted the connections between the clamp and those wires. Similarly check the wires on the - post clamp and trace them to their respective ground points and verify clean tight connections at the far end. Then let me know if that hasn't helped and I will look for the possibility that one of the several sections of the ignition switch is flaky in the 'run' position such as to impact these several circuits you are having trouble with." Perhaps the best thing would then be to look at each of the problems separately: On the front wiper won't stop problem to begin with, the manual suggests checking out the switch itself which is part of the multifunction switch and involves reading resistances between 2 of the 4 pins of that switch's plug socket. You must remove the upper and lower steering column shrouds to get to the switch. Also the problem could be due to a poor ground connection of the wiper 'park' switch which is involved in maintaining the wiper motor operation and then in stopping the wiper motor at the park position. As I read the circuit, there is a brown/gray wire between pin 7 of the numper 7 plug (black exterior, red interior) of the integrated power module and which is connected to the parking switch inside the wiper module. That switch is either open or grounded depending upon the position of the wiper arms. If the switch contacts inside the module were oxidized or otherwise impaired then the message to turn off the wiper motor would not be received at the ipm and that would explain why it won't shut off. So find that wire either at the ipm or the module and see whether it is changing from open to grounded when you turn the wipers off (or possibly vice versa). Do you have an ohm-meter? I would appreciate another rating and nomination if you are being helped. Roland