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When car body computers go bad: strange interior behavior, instrument cluster or gauge failure, and other issues

The CTM, or Central Timer Module, is, to put it simply, the brain for the interior. It does a great deal more than just time things out. It is the electrical hub for the entire interior now. While replacing mine I was told by another fellow that he had to replace the one on his 1979 Chrysler many years ago. So, they are not a new thing except to us.

In my case, the interior of my Dakota seemed to take on a new life. Quite a few things failed or just worked wrong. My first response was to unhook the battery and let the system lose power completely. When I hooked the battery back up it worked fine for a day or so. Weird things kept happening though. I don't need to bore you with details of the symptoms yet. [Editor’s note: on most cars, you can remove a single fuse, the IOD fuse, for 20 minutes. This will reset the interior systems, and is essentially the same as removing the battery, but somewhat less severe and easier to do. Thanks, Joseph Kan, the Schroms, and Gary A.]

I finally started scanning the wiring schematics in my Haynes manual for Durangos and Dakotas. We all know how bad the wiring schematics are in Haynes manuals but it fortunately had just enough. I individually checked the schematic of each component that was not functioning properly. All of them were linked to the same thing, the Central Timer Module. After seeing this, my troubleshooting was over. I picked one up from the local dealer and put it in. It would have been a simple and fast fix if I'd known it was located behind the driver's kick panel.

The old problems are gone now. One new thing did happen. I should have expected it. My keyless entry does not work because the new CTM and my key fobs don't know each other. I just talked to the Dodge dealer today and they said that only they have the software to do that. He said it was only $40 and 1/2 hour of work.

Editor’s note: similar problems have occured in minivans, cars, and other trucks; in some cases the systems work erratically, in others they fail completely. The fuse-pull reset often works temporarily, but if the CTM or “body computer” is bad, the problems reappear.

Also see climate control troubleshooting and checking computer codes (which often does not include the CTM)

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