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Dodge Repair/'02 minivan: accessories don't work when engine is running

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QUESTION: Hi,...My fathers 2003 Dodge caravan has been acting up electrically lately and i cant seem to isolate the problem....Everything works fine,.... Radio, Blower, Wipers,Windows etc,....while the engine is off,.... u start the engine, the accessories will turn off while the ignition is on start as they should but when the engine starts, they will only come on for 1 second then turn off,.... They will not work with the engine running. I have tried another fuse box,,,, another Body control Module, cleaned the ground in the passengers side door post, no change,.....The only way to get this stuff to work is to run a ground wire to each affected relay in the fuse box...If you could please suggest something else to try, it would be greatly appreciated.... Thanks,
Barry

ANSWER: Let me study the wiring diagrams and get right back later this evening, Barry. In the meantime, will the accessories work when the ignition switch is in the 'run' position but with the engine not running? Let me know that, and also what happens when you have the key in the 'accessory' position.
Rolsnd

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QUESTION: Im not sure about in the "ACC" position and i dont have the vehicle here now but u can turn it on "run" without starting it and everything works fine,....when u to turn it to "start" everything shuts off, as it should, when the engine starts and u release the key to "run" again, the blower will give a 1 second blast and all the accessories shut off,.... nothing will work with the engine running...... THX

ANSWER: Hi Barry,
The body control module is probably involved in this problem but you replaced that.
So I notice that the ignition switch's key position is 'told' to the bcm by means of various voltage levels that come from the switch which are based upon 6 different resistors inside the ignition switch. But the resulting voltages depend upon the primary voltage that enters the switch before it goes through the various reesistor pathways. My first thought is that either one of the switch poisitons or one of the resistors in the switch is marginally conducting or off-value such as to cause a different result voltage in the run position depending upon whether the engine is running or not.  Or more likely, it may be the case that the voltage regulation of the alternator is faulty such that the voltage level on the system is not where it should be when the engine is running which then causes the bcm to mis-read the position of the key.
I would measure the battery voltage at rest with the key in the run position, then read the battery voltage when the engine is running asd let me know what those two reading are.
And to corroborate this theory you could compare similarly the voltage reading at pin 14 of the black/gray 34-pin plug of the bcm (violet/orange wire) that comes from pin 1 of the ignition switch WHEN the engine is not running (key in run position) vs WHEN it is running. I would suspect that there is a discrepency in those two voltage readings which is causing the bcm to not behave as it should. Let me know what you learn, please. Just prove through the violet/orange wire with a fine pin to do your voltage measurement.
Please 'rate' my answer(see below).
Thanks,
Roland

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QUESTION: Sorry 4 the delay,..I brought the van to my place, i have no garage and the weather sux lately,...I tested the battery with the key on/eng off and it was 11.40V which i know is low, and guess shes in need of a new one....The voltage with the eng running was 13.99V, which sounded good to me,.... Tho its not an easy spot to get your head, I checked all the wiring going to the BCM and could not find a voilet/orange wire,... i did find a purple/orange one tho,... the voilet is usually a lighter shade so i dont know if this would be the one or not. However i did measure the voltage on this one anyway and it was .54V with the engine on or off,... no change,.... Please let me know if there is a purple/orange wire on the BCM in the schematic as well as the Voilet/orange one u spoke of and ill have another look..... Thanks
Barry

Answer
Hi Barry,
There are 4 violet/orange wires on the five plugs of the bcm. On the third black/white 34 pin plug at pin 29 is a liftgate ajar sense switch, then on the fourth black/gray 34 pin plug there are three of the same color wires on pins 14 (ignition sense return, which is the one which should vary with different positions of the key), 22 (multi-function switch 'mux' return), and pin 34 (chime driver). The pin 14 ia the one you would measure the voltage on with the key in the various positions, and the engine both running and not running in the 'run' position where the voltage should be about the same and at least should not appear to be a voltage shown by any other of the switch positions. No purple/orange.
Please rate my answer.
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 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" from 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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Degrees in Physics/bruised knuckles.

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"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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