2002 Durango. Vehicle starts, runs, and drives fine.

Intermittent Electrical Problem:

1. Dash indicator lights for Door Ajar, Gate Open are not working.
2. Indicator LEDs on 4WD selector Switch Not working (should be lit at "2WD")
3. No key in ignition chime.
4. No Door Ajar, Gate Open Chime.
5. No low fuel Chime.
6. Service 4WD light on.

Intermittent Problem:

When driving the SUV, and with no regularity, the Service 4WD light goes out, LED on 4WD switch turns on, Door Ajar and Gate Open indicator lights function. All chimes work. Auto Lock Feature kicks in and locks the Doors. Most of the time, this will keep working until the vehicle shuts off. If started back up, all of the systems still function normally. If left for a while, the system returns to the exact problem situation outlined above.

Electronic Control Modules (ECMs) Involved:

1. Transfer Case Control Module (TCCM).
2. Central Timing Module (CTM).
3. Transfer Case Selector Switch (TCSS)
4. No other known modules at this moment.

Scanning of wiring schematics from factory service manual confirms the following shared connections of these three ECMs:

1. G207 (Ground Point 207) Checked and ground confirmed with ohm meter. (CTM, TCCM)
2. PCI Bus at Diagnostic Junction Port (parallel connection point before Data Link connector (No DRB111 to check bus information with) (CTM, TCCM)
3. Fuse 11 Junction Block, A21 Run-Start off of Ignition Switch. (CTM, TCSS)
4. No other shared connections found as of yet.

Observations:

1. CTM is processing door locks, window controls, Interior Lights, All exterior lights, etc.
2. All hard connections are working at the CTM.
3. TCCM module is not tested because I don't want the Durango stuck in 4WD.
4. Key-in Ignition Warning Enables when key pushes key cylinder inwards. (Possible Bad Ignition switch, or key cylinder).

Suspect no Data being sent to the Electro-Mechanical Instrument Cluster (EMIC) Module on PCI Bus, or problem with Fuse 11 in Junction Block (Driver's side fuse panel).

Troubleshooting continues.

 

Schematic path for fuse 11 in Junction Block (Driver's side fuse panel). Disconnect all battery terminals (both terminals) for 30 minutes and leave disconnected:

Circuit begins at Battery into Fuse E at Power Distribution Center (PDC). Circuit leaves PDC at Terminal E with Wire A19, #16 Guage Wire (Red with Yellow Stripe) to Pin 15 of Conector C200 (very large terminal block under right dash near the inner firewall of the Durango). From Pin 15 out of C200, Wire A19, #16 Guage Wire (Red with Yellow Stripe) goes to Pin 4 of Ignition Switch. Out of Ignition Switch Pin 3, Wire A21, #16 Guage Wire(Dark Blue) goes to Junction Block hard-wired point #21 and through Fuse 11 (10A). From Fuse 11 Junction Block hard-wired point splits across Connectors C3-Pin 7, C5-Pin 2, C5-Pin 5, C10-Pin 9, C10-Pin10.

Possible cause for problem is at:

1. Faulty Wire connections of ignition circuit.
2. Fault Ignition Switch.
3. Faulty Connector C10 (supplies both CTM, and TCSS which feeds TCCM).
4. Faulty Distribution bus connections in Junction Block at Pins 9 and 10 for connector C10.

Regardless, verify continuity of circuit from (disconnected) Battery to connectors for CTM, and TCSS.

1. Connector C3, Pin 7 at Junction Block feeds AC Compressor Clutch Relay (which works), and Proportional Purge Solenoid in engine bay (No check engine light so assumed to be working at the moment).
2. Connector C5, Pin 2 at Junction Block feeds Automatic Day/Night Mirror (Don't think my Durango has this accessory).
3. Connector C5 Pin 5 at Junction Block feeds Overhead Console (My Durango only has dome lights, so unsure if I have this accessory).
4. Connector C5, Pin2 Feeds
5. Connector C10, Pin 9 at Junction Block feeds Central Timing Module (CTM). Connector C10, Pin 10 Feeds Transfer Case Selector Swtich (TCSS), which supplies information to TCCM, which means bad input to Transfer Case Control Module (TCCM) sends error signal to EMIC.

Steps

1. Turn ignition switch on and verify from Ignition Switch Pin from Ignition switch to Fuse 11 to verify continuity from Fuse E, to Ignition Switch pin 4
2. If continuity is good at Ignition Switch then Verify continuity from Pin 4 to Pin 3 of ignition switch (verify Ignition Switch is good).
3. If continuity is good through ignition switch, then verify continuity from Ignition Switch Pin 3 to Fuse 11 of Junction Block (verifies continuity of wire and distribution through Junction Block).
4. If continuity is good then check for continuity from fuse 11 to Connector 10, pin 9 and pin 10 in Junction block (verifies good junction block distribution).
5. If continuity is good to Connector 10, pin 9 and pin 10, check female terminals of connector 10 plug. If female connectors look stretched repair as necessary, and connect Connector 10.
6. Check for Continuity from Junction block fuse 11 to Central Timing Module (CTM) Connector C1, pin 25. Inspector connector receptacle and repair as necessary.
7. If continuity is good, Check connector (unmarked) at Transfer Case Selector Switch, Pin 7. Inspect female connector and repair as necessary

If continuity is good verify all connections. Reassemble and check operation.

 

Just spent the day troubleshooting the electrical circuit for TCCS/TCCM and CTM module using my Fluke 87 DMM. I'm scratching my head here.

1. I started at Fuse E. I pulled Fuse E and did a continuity test and the fuse checked out fine.
2. I then did a DC voltage test at the PDS to ground and got 12.86Vdc. So, the battery is feeding the line side of the fuse holder.
3. I pulled the steering column cover off , pulled the connector off of the the ignition switch and ran a continuity test from the load side of PDS to the ignition switch terminal on the connector. It was good.
4. I put the connector back on turned on the ignition switch, unhooked the battery and ran a continuity test from the terminal on the backside of the ignition switch to Fuse 11. It was good.
5. I then ran a continuity test of Fuse 11. It was fine. I then ran a continuity test from Fuse 11 to the terminal on the CTM module. It was good.
6. I pulled the floor carpeting and ran a continuity test from the ground side of the CTM module to the copper crimp terminal. It was good.
7. I then ran a continuity test from the copper terminal to the Knee Guard metal on the dash to make sure the ground was getting onto the steel of the vehicle. It was good. I pulled the connector off of the CTM and checked the female connectors and straightened them as best I could and put the terminal connector back onto the CTM.
8. I then reinstalled Fuse E, connected the battery terminal, and went in and turned the key to on. I got nothing on the instrument panel for Door Ajar, or Gate Open. I still had no indicator light on the TCSS module.
9. I started the Durango up and checked the voltage at fuse 11 to ground and got 14.2Vdc. I then checked the voltage on the back side of the connector to the CTM and got the same reading. I then check the voltage at the negative of the CTM and got Zero volts.
10. I did not check the TCCM because of its inaccessibility.

Like I said before, both the TCCS switch and the instrument display would come on erratically. And I'd like to clarify that they both came on at the same time and worked flawlessly.

After reading the schematic from the Factory Service Manual, the weird behavior says that a bad ground should be the problem since they are both fed on different wires from the Fuse 11 bus inside the Junction Block.

I finally pulled the connector on the PCI bus at the junction and checked all of the pins and connectors there.

Everything looks fine, everything seems to test fine, but neither will work. But when they do work, they both work flawlessly.

Any ideas from the pros? Can a bad TCCM module cause no data to be sent from the CTM onto the PCI bus up to the EMIC?

I'm an electrician and an electrical engineer, I know my way around wires and electrical test, and I'm scratching my head on this one. It makes no sense.