I have a 99 Grand Caravan LE, 3.8L, electric windows, door locks, remote entry (fob), and no security system. I have several issues that by looking at a Chiltons manual electrical diagrams (that aren't always correct or complete) that makes me believe my BCM is bad or on its way out. Here are the symptoms.....
No instrumentation, cold solder joins previously fixed, and instrumentation worked fine. ABS light on , service light on due to needing new EGR valve. no front or rear windshield washer pumps work, no rear wipers working, front wipers work but park in place when turned off,(wont return to bottom of windshield on their own), When you step on the brake the front turn signals light up and stay on like marker lights until you release the brake. When doing this the display on the radio goes dim like there is a short to ground or a insufficient ground. I tried to conduct the instrument panel test but there appears to be no voltage there at all. I couldn't get the display to light up at all. I was told the other day that my right brake light doesn't light up when the brake pedal is depressed. I plugged the right tail light assembly into the connector for the left side and it worked fine. There seems to be a ground issue or the BCM is bad. The Chiltons manual looks like there are two (2) common spots to explain the trouble I am experiencing. The first is a left side cowl ground (which I can't seem to locate on line) or the body control module. Before investing in a BCM and having it programmed and hope it fixes the problem I thought I'd ask any of you members for some advice as to where to begin my trouble shooting of the quest.

 

You may have a total bus failure. You need to scan the modules, all of them and find out which module are not on the bus circuit. I had a 2001 minivan last month, the radio took the 2.5 volt bus circuit down and the van had the same problems you are having. I'm not saying the radio is your problem. You can try unplugging modules one at a time and see if the cluster lights go out or take the vehicle to a shop.

 

Thank you for the reply...Are you referring to the CCD positive and negative bus? Additionally I noticed tonight onthe way home from work with the headlights on I had a faint glow from my parking brake light. Once I got home had the headlights turned off but the ignition switch in the run position set the emergency brake and both headlights came on and stayed on even after releasing the e brake. In order to get them to turn off needed to start the van and cycle the headlight switch to on then off and then turn off the igniton before they would turn off. I did a test this morning on the overhead console, ie reset it. The elaped time mpg and other would light up but would not change like the ccd buss was out. the ambient temp works as does the illimination light for the dash board and other accessories. I was wondering where do I start troubleshooting the bus(s) you are referring to? I would appreciate any help you can provide since this is my daily driver and I am afraid the some morning it is just going to leave me stranded because of the electrical issues.

 

You referred to scanning the modules???? Who does this, a shop or can a lay person like me do it? If so what test equipment do I need? I am pretty mechanically inclined and can use a volt/ohm meter but need guidance on where to start and what I should be looking for, ie..5v positive and 5v negative on the bus?

 

I am having a similar problem. I don't know why my heater control is burning/melting the plug on one pin and shorting the wire across to the bus circuit. When it shorts it kills all of the instrument panel and turns on the ABS light. As soon as I jiggle the wires it will come back. Anyone know why the heater control should be getting so hot on one pin. I don't have a wiring diagram handy but I think it is a ground wire pin that is the problem.

 

panama63 I'm sorry I can't wade in and give you any advice or help. I'm not a mechanic/technician just a working guy that is some what mechanically inclined that was hoping someone who is a mech/technician could help get me going in the right directio to fix these problms.