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Chrysler Repair/1997 Dodge Grand Caravan 3.8L Transmission Gear Indicator Problem

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QUESTION: 1997 Dodge Grand Caravan 3.8L Transmission Gear Indicator Problem

A couple of weeks ago my 1997 Dodge Grand Caravan 3.8L transmission gear indicator and transmission started acting up.  The symptoms are:  most of the time when I go to put the van in gear either all of the gear indicator boxes will light up (PRDN21) or none of them will light up.  Additionally, some of the time when I move the gear selector handle, nothing will happen, or a gear will be engaged with or without the gear indicator boxes lighting up.  Additionally, most of the time the N or neutral gear indicator box does not light up even when I know –--the car does not go back or forward and the engine revs when I apply throttle pressure--- that the car is in neutral.

Lastly, almost every time I move the gear selector handle from D(rive) to R(everse) at normal speed, the car engine dies and I have to restart the car.  Some of the time, if I move the gear selector handle from D(rive) to R(everse) at a very slow speed, the car engine will stay running.

I have run a consumer grade “Engine Check” computer on my van and no codes appear, even among the transmission code sections.  Does anyone know if there is an “Instrument panel electronic self-check” that can be run on the 1997 vans?  I have already tried to use the “Trip Reset” button (turn the engine off,  hold the reset button down, turn the key to the “ON” position and look for any codes) and this did not bring up any software versions or code information.

I have done some research on the potential causes for the symptoms described above and, it appears to me, that the most frequent cause is for the van’s instrument panel to have a loose and/or broken solder joint.  Right now I have removed the van’s instrument panel and am awaiting the arrival of a new solder gun in order to re-solder a couple of suspected solder cold joints.

Can anyone tell me, other than the instrument panel solder issues, what other problems may be causing my transmission gear indicator and transmission problems?  Just in case the van’s instrument panel is not the culprit, I want to be ready to look into other possible causes for the gear indicator problem.

Thanks In Advance!

ANSWER: Hi Paul,
The problem could either be in the digital data bus circuitry or the cluster itself, but I suspect the former. There is a cluster diagnostic capability (according to the '98 manual) and it involves the approach you tried except that you push and hold both the TRIP and the RESET buttons, then turn on the ignition, then wait 5 seconds until CODE appears in the odometer window then release the buttons and observe for codes and watch as it runs through some self-testing. Let me know what happens.
As for the data bus, that is carried on a twisted pair of wires between the trans control, the powertrain control, the body module control, and the cluster. The white/black wire connects as follows: TCM pin 4          
        PCM pin 60          
        BCM pin 34          
        Cluster pin 9          
while the violet/brown wire connects:
        TCM pin 43
        PCM pin 59
        BCM pin 3
        Cluster pin 10
So you could check the continuity of those two wires between the various pins and shake the harnesses as you do so.
Please 'rate/nominate' this answer/me (see the PS below).
Thanks,
Roland      

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

QUESTION: Good information.

Will any defects in the the digital data bus circuitry show up in the cluster diagnostic tests?

Am I reading your twisted pair wire info correctly.  For example is it true that their should be continuity completely between any of the various controllers.  Lets say I have one end of my tester on TCM pin 4, should I then be able to get a continuity reading between any of the pins numbered 43, 59, 3, or 10?  

When counting pins on PCMs, BCMs, and clusters is there some convention as to which pin to count first and then what number pin is the one directly adjacent to it.  For example, if I disconnect the TCM and look at the male end...is the top pin to the furthest left the first pin...and the one to the right of that the second pin...and the one on the far left of the next row numbered one more than the pin at the far right of the row above?

On my '94 Mopar van the TCM was on the firewall.  Where are:  the TCM and the BCM on a 1997 Dodge Grand Caravan?

Answer
Hi Paul,
No TCM 4 would be continuous to 60, 34, and 9 while TCM 43 to pins 59, 3, and 10. The plugs will have a number showing for each pin of the plug where the wire comes into the plug/ The PCM is on the right inner fender in the front corner, in front of the shock tower. The BCN is under the dash, behind the fuse block (junction box) and it has 2 plugs on the bottom side of it which are accessible by simply pulling down on the plugs.
I would really appreciated a 'nomination' if you are so-moved.
Roland  

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Roland Finston

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Get a Free Fast answer to your repair question about a Chrysler/Dodge/Plymouth car, minivan, SUV, or truck. Problems with electronically controlled engines and transmissions as well as body wiring problems are my specialty. This free troubleshoot advice forum helps you diagnose faults, minimize repair costs or do-it-yourself.

I answer questions seven days a week and respond to you in about 30 minutes. "Maxed Out" means I am answering another question, briefly unavailable, or asleep overnight, so try again later.

I have do-it-yourself experience (50+ years) and a library of 100 1982-2012 Chrysler factory shop manuals and 20 multi-manual Chrysler Corp. CD's.

I was voted "Top Expert" 2010-2015, here at AllExperts, and have answered 20,000+ questions.

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Five decades as a 'do-it-yourselfer' on domestic and imported cars.

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Yahoo Autos Group called The Chrysler Lebaron Club (co-moderator)

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Advanced degrees in Physics/bruised knuckles

Awards and Honors
"Top expert" of 2010, 2011, 2012, 2013, 2014 and 2015 here at Allexperts. Quickest "average response time" at Allexperts (currently no. 1).

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