BCM Location?

I have a 1990 Dodge Grand Caravan that I’m having electrical issues with. It was suggested that I check out connections to/replace the BCM, but after looking on the web and in my Haynes manual, I still can’t figure out where it even is. Anyone know? I know the ECU is next to the battery, and there is some kind of computer bolted on the firewall behind the alternator, but I’m under the impression the BCM is in the dash somewhere and it doesn’t look like the pictures I’m seeing. What’s that thing on the firewall?

Also, as long as the OE matches, it’s possible to get this part from a different kind of car, right? Web search results yield information about the Le Baron and some trucks, but no mention of the Caravan anywhere.

Have you looked under the dash by the brake pedal?

I don’t see a BCM mentioned among the modules. These are the only modules listed:

Chime, daytime running light, fuel gauge damping, gauge alert, WW, key-in, overhead console, seat belt warning, engine controller.

I’ll check there, I didn’t even know where to look. And I wasn’t sure it’d have one either, George, because I don’t have automatic windows or locks or anything but upon calling the dealer to try to price it, they were able to give me OE numbers. I know it runs the air conditioning on some models too. I was about 5 minutes from putting in a new ECU 2 days ago, but it occurred to me that if there was a short or something causing the issue, it could ruin the new ECU and 300 bucks would go out the door in a flash. This thing is throwing a code for a short or open circuit in the cruise control servo too, and it doesn’t even have any damn cruise control. Not sure what I’m supposed to do with all that mess.

There is a reference to a Body Control Module, but the diagrams for that are the powertrain control section. I expect you already know the powertrain control computer (aka ECM/ECU) is located near the left fender side shield.

According to what I see, the powertrain control module is what controls the air conditioning and the charging system.

Maybe it is different w/different configurations. Which engine do you have? Is it the V6-181 3.0L?

Maybe a better question is: What is the actual problem you are trying to solve? Why do you want to replace the BCM?

A 1990 Caravan doesn’t have a body computer. The next generation (AS body) was the first caravan to use a body computer. The computer on the firewall is the transmission control module (3.0L, 3.3L).

I don’t see a relationship between the problems you have, monitoring the voltage/ground should reveal a problem. It was common to see low battery voltage trigger the rear wiper but not the front.

The first step I would take is to remove the front kick panels and tighten the lower instrument panel bolts and wiring grounds. This may cure electrical problems in the cab but probably not the stalling problem. The stalling problem is usually caused by a failing idle control motor.

With no cruise control servo connected the cruise control open circuit fault is normal, ignore this.