Archived "4LO" Actuation with Key Fob - Need Dodge Electrical Engr Help

[Stref]

Enough is Enough!!!!!!! This is a "Buy Back" truck. It was purchased by the first owner in Nov 2009, and turned-in for buy Back in Apr. 2010 due to this problem. It should have been fixed by Dodge before release, but was not because the problem cannot be duplicated at will. I have had the truck for 18 months and been to several dealerships, and currently have an open case with the Dodge Customer Service Center with no resolution so far. Thousands of dollars of warranty work have been expended because no one is trying to analyze the problem. I need help from someone who knows the electronic 4WD system inside and out, including the signals and paths to the shift motor. There have been many occurrances of this actuation, including going into 4WD without manual input, but I want the expert to dwell on this one only:



With the truck sitting overnight, and not touching it, unlockiing it with the key fob will sometimes cause the 4LO to actuate one time. It will not repeat on sebsequent key fob input.



Please message me for follow-up phone call. The truck description in the signature is accurate.

 

[Sticks]

Another one of those fun things that should not happen but apparently is.



The simplest explanation is a bad ground and the door unlock/security disarm is back feeding through the 4wd circuit.



One can't really fault Dodge on not being able to find the problem if the occurrence is that rare. Electrical bugs are hard enough, but when they are random or only happen even once a day, it is near impossible to find and fix short of replacing the entire electrical harness for the affected systems.



I've had all manner of goofy crap go on with turn signals and a backup alarm (left turn signal would flash the right side, right turn signal would flash the left side and activate the backup alarm, hazard would flash the clearance lights - unrelated circuit - and nothing at the tail) on a Mack Truck that all boiled down to a bad ground at the tail light.



If those of us who can read an electrical schematic, and have access to it, pour over it for a few days and discuss it can't find it, I would recommend having the OEM door unlock and security system removed and have an after market one installed. This might also come down to a bad PCM (or other control module - chassis).



We would also need to know the entire history of repairs to the truck since date of original purchase, and what dodge may or may not have done prior to the buy back. This would include any and all components replaced.

 

[Bob4x4]

I empathize with you but buying a lemon knowingly?? Buy the service manual and start studying on the involved systems. No one will be able to spend the time like you can. The factory will not pay anyone the time it will take.

 

[HBarlow]

Stref,

Does AZ have a lemon law that works to support consumers with problems like this? If so, get a copy and study it to see if your case is eligible.

PM sag2 who is apparently a Ram factory service rep or dealer service tech and very knowledgeable.

 

[Bob4x4]

Lemon laws are for origional owners only

 

[Bob4x4]

Has the star center been involved or is your dealer throwing parts at it?If your warranty is close to expiring has their been a cair case opened?

 

[Stref]

I believe the Star center was involved when the truck was taken to Larry Miller Dodge in Perora, AZ, my home dealership. I don't know what "CAIR" is but as I said in my post, there is an open case with the Dodge Customer Service Center. My contact there has been very good at following-up and speaking with the dealerships involved. I am currently spending the summer in northern AZ, so am working with Planet Dodge in Flagstaff, AZ. A problem is that one dealership will not continue where the previous one left-off, which is evident by the following list of work done so far by various dealerships:

1200 miles, TIPM, shift motor and wiring harness, $900. 00
1450 miles, diagnostic time, $100. 00
1500 miles, shift motor and wiring (same parts as 1200 miles), $750. 00
4100 miles, transmission harness and fuel rail, $1000. 00
7700 miles, trans harness (same part as 1200 and 4100 miles), $200. 00
15,000 miles, shift motor, $350. 00
15,600 miles TIPM (same part as 1200 miles), $450. 00

In addition, another wiring harness will be replaced due to two wires whose colors do not match those on the wiring diagram, even though I traced them and they go where they are suppose to go.

 

[Stref]

I like the idea of a bad ground, because it seems to make the most sense. I might add that I have no other problems with the truck. The electronic 4WD works as it should when using the switch on the dash. According to the wiring information the grounds are on the TIPM and inside of the door panel. Is this correct?

 

[dlmartin]

If you don't use 4LO any more than most people, a practicle solution might be cut the engagement wire(+) to the motor LO and "T" in a manual swith and leave it open until you need to engage 4LO. I haven't looked at a wiring diagram, so this is just a guess.

 

[Bob4x4]

If you don't use 4LO any more than most people, a practicle solution might be cut the engagement wire(+) to the motor LO and "T" in a manual swith and leave it open until you need to engage 4LO. I haven't looked at a wiring diagram, so this is just a guess.

nope wont work and will set a dtc

 

[Stref]

It appears that the problem has been found by Planet Chrysler Jeep in Flagstaff, AZ. The 5 volt supply to the T-case Shift Motor was intermittent due to a defective female pin in C130. The spring tab inside the female pin that pinches the male pin was bent flat. If anyone can tell me how interruption of this 5 volts supply will cause the system to want to go into "4LO" from "2WD" I would appretiate it.

 

[Sticks]

The tech that found the problem should be able to answer that question. Fun things start happening when voltage get's back fed into components, or components start to draw too much amperage, yet be under the circuit protection limit.

I work for a concrete paving company that has one unit that is now on it's 3rd shutdown solenoid (8. 3L Cummins, single wire solenoid) in 2 months. Every time the solenoid starts to go TU, I get all manner of interesting problems with the elevation and steering sensors, and no problems are ever the same. This last go around ultimately left it unable to move at all with 80 yards of fresh concrete in front of it. After 30 minuets on the phone with tech support, I noticed on an engine restart that the solenoid was not closing without assistance and disconnected the power wire. All the problems went away.