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Discussion Starter #1
My 91 Grand Voyager transmission is acting up. After a few miles, It goes to low gear when I slow down and stays there. Also, my fuel and temp gage don't work. But when the trans acts up the gages start working correctly. I know this is a wiring or computer issue. I got this van from my grandparents. It had trans work done before but I'm not sure how long ago. I don't know if the trans job had anything to do with the gages or not. My grandfather passed away in the late 90's and I can't remember him saying anything about any of this. It only has 140,000 miles on it. I would like to try and get this fixed. It's not a bad daily driver. Any body have any ideas? I hate to have to put a computer on it if I can even find one.
 

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hmmm that sounds like a doozy. I'd maybe look at a wiring diagram and see if the gauges and anything with the transmission (sensors, grounds, computers) share a ground, fuse, or relay. If they do I'd start there
 

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They may share the communications bus that shares information between modules. A fault code from the TCM (transaxle control module) may give us some clues. It sounds like the common thread here. The gauges would drop out when the bus goes down.
If you can get the TCM scanned for fault codes and a wiring diagram, you may be able to fix this.
The 'twisted pair' communications bus wiring would have its weakest spots at the terminals and connectors. Usually a violet and white wire pair. Look for corrosion, rub-throughs, pinches and wire breaks. Wet connectors can short a bus.
Being intermittent makes it harder to find.
 

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I'll try and get the ECM read today. I'll let you know what I find. Also, a week or so back when driving, all the dash warning light would flash on and off and the door locks would lock. They were already locked. It was like the computer was telling them to lock like they do when you get to a certain speed. It was almost rhytmatic. Now that I think about it, it could have almost been a code. Does this year have a self diagnosis. I know on my later model Dakota you can turn the ignition switch on and off a couple of times and the check engine light will flash any stored codes. The check engine light is not on in the van.
 

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The same check engine light flash will work on the van.
The door lock/unlock cycle is often a sign of a bad switch at one of the doors, often the sliding door. But it could also be a failure somewhere in the wiring which may be the common point for all your failures.
 

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The ECM (or PCM) is a different module read at a different connector than the TCM. The transaxle limp-in (2nd gear) cause may not show up on the engine controller (underhood connector). You want to scan the transaxle controller - TCM (underdash connector).
Being OBD 1, you will need a capable scan tool with the Chrysler-specific cables.
An engine fault may light the 'ck eng' light and show codes via the key-dance, but a transaxle fault may not.
 

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My oldest brother had a Town and Country van that started having the door lock problem you mentioned. After taking it to the dealership where he got it, it was a defective BCM. Maybe yours just has some corrosion on the plug. I'd try using some good electrical contact cleaner on it and then plug it in an unplug it several times in order to "sweep" the contacts clean too.
 

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I was getting ready to go out and do the contact cleaner. Okay, I see the the ( I don't which one is called what, so I wil call them "boxes") "box" located on the left side behind the battery and the "box" located on the right side upper firewall engine compartment. So far there have been three "boxes" mentioned. The PCM, TCM and BCM. Which one is which and where is the third one located? ImperialCrown you may have a point about getting it read with the correct connectors. I live in a small town and don't think anyone here has the correct adaptors for some thing this old on a Saturday. I'm going to check all the connectors and grounds that I can find, underhood and underdash. Thanks for all the help guys!
 

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PCM is by the battery. TCM is on the right side firewall and the BCM is under the dash. They are modules. Actually disconnect and reconnect the connectors to 'scrub' the terminal contacts together.
 
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