2nd Gen Non-Engine/Transmission Instrument Cluster Troubles (long)

[AggieJustin]

OK, I'm hoping that someone here has seen something similar before and can help me out. I'll apologize in advance for the long post... .



I had posted here before about having trouble with the gauges on the instrument cluster going dead and all the warning lights coming on. It would usually happen either when I started the truck, or when I let the truck sit and idle for a few minutes with the parking brake set. Basically, I'd get the Brake, Air Bag, ABS and MIL lights. Then the gauges would start going dead. The overhead display would show Ccd and the odometer showed 'No Bus'. Usually, releasing the parking brake would clear it all up.



I had previously thought it was a bad connection, so I checked the plugs under the dash and in the engine compartment. It finally got so bad that it would happen every time I started up, so I took it in to the dealer. The checked it out and determined it was a short in the cluster, so they replaced the cluster.



When I got the truck back, everything was working normally. I plugged my EZ back in and went on my way. Later that night, when I went to start the truck... . the same thing happened again. Then when I let it sit and idle, same thing as before. I tried repeatedly after that to try to make it happen again, but I couldn't recreate it. I was thinking that it could possibly be something wrong with the EZ, so I unplugged it... . but it ended up happening again after the EZ was removed.



So now it's been at the dealer for a couple of more days, and they've been over all the connections and haven't found anything that looks wrong and they haven't been able to make the same symptoms appear again.



Does anyone have any ideas about what to check now??



Edge said they could swap my EZ for a new one if I wanted, but they've never heard of one causing this problem.



I'm completely and was hoping that someone might have some suggestions for me.



Thanks,



JM

 

[emjay]

Man, that's a tough one. Judging by your symptoms and the fact that releasing the parking brake made it go away, I'd have to say that possibly a wire is pinched or has damaged insulation under the dash. The CAN bus is a twisted pair, you could try running a new pair from the PCM to the cluster, but that might get hairy due to the airbag connections and whatnot. If it were me, I'd remove the cluster and get a close visual on as much of that network wire as humanly possible. If it's under warranty, you can try to make them replace the harness Personally, I wouldn't trust 'em though. Do you have a shop manual? If so, you can trace the route of the harness. If you can pull and yank the network wire while it is idling, or maybe even key on, engine off, you may be able to reproduce it.



There may be more advanced troubleshooting methods involving CAN bus analyzers, but that's likely beyond the capabilities of the dealer. Sorry I can't be more helpful. Good Luck!

:{

 

[fest3er]

If it is saying 'No Bus', then there is likely a wiring harness problem *anywhere* where the CCD bus runs. Given that the ABS and brake lights come on first, it *could* be a short under the hood. It *sounds* like the entire CCD bus is going away, not just the instrument cluster.



Remember that the CAB, ECM, PCM, instrument cluster and perhaps other things all communicate using the CCD bus.



And, for those who are wondering, CCD stands for 'Chrysler Collision Detect' It has nothing to do with physical collisions. Rather, it refers to two or more devices sending simultaneously - thus their transmissions 'collide'.



Fest3er

 

[emjay]

Agreed, but when he releases the parking brake, it returns to normal. That's a big thud in the dash area.



If the physical layer of the network is a CAN bus (I believe it is), the devices or connectors at each end of the bus should have termination resistors in them. In theory, you could isolate non-critical devices (like the overhead console, or the radio) by terminating or bypassing them, depending where they're physically positioned on the bus.



Any way you look at it, it's a tough job, especially given the intermittent nature. That's why I suggested pulling and tugging to possibly trigger the fault and isolate it to a smaller area.



Too bad you're not closer to the San Jose CA area, that sounds like a fun challenge.

 

[AggieJustin]

Thanks guys.



I'll probably go do some more checking on those wires tonight... . see if I can find anything that will set it off.



Just as a side note, is the bus that the cluster and overhead display listen on, the same bus that that would have the connections from the MAP sensor and the data link connector that the EZ plugs in to? So far when the problem has shown up, it's been with the box plugged in... . or right after I removed it (basically no miles just a couple of key on cycles).



Since the problem hasn't shown itself for four days now, I'm probably going to plug the EZ back in. If it happens again, I guess I'll take Aaron up on his offer to swap boxes.



JM

 

[emjay]

I'd have to double-check the manual, but I'm pretty sure that there are two busses -- one for the Cummins ECM and the other for the Chrysler PCM. IF that's true, than the EZ should be on the Cummins bus.

 

[emjay]

Ground Connections

Good point, slo-ryde. Floating grounds can cause very strange symptoms. I worked on a Buick many years ago that was reading minus 8 volts to ground at the fuse box. It was the lack of a ground from the engine to the body that caused that. Needless to say, all the gauges were reading wrong.



Keep in mind that a short on the CAN bus will probably not blow a fuse, because the signals are fault-tolerant and current-limited to prevent permanent damage to the transceivers in the event of a short or other electrical fault.

 

[TradedV-10foraCummins]

I came across a TSB that might apply to the problem you are having. Here is the link: http://dodgeram.info/tsb/2000/08-05-00.htm .

 

[emjay]

Exactly! Good job, TradedV-10foraCummins!



Since that TSB is for 1999 model, you probably won't be able to get them to apply it, but it should narrow the focus quite a bit.



Cavity 9 & 10 are the CCD Bus.



The whole pinout is:



1 N/C

2 Fused Ignition Switch Output (ST-RUN)

3 Park Brake Switch Sense

4 Ground

5 Ground

6 Fused B+

7 N/C

8 Wait-to-start indicator driver

9 CCD Bus -

10 CCD Bus +



You might want to double-check the two grounds. Also, If it is a ground problem, the non-networked indicators, which include:



instrument panel illumination

wait-to-start indicator

washer fluid indicator

seat belt indicator

tone request signal

turn signals

high beam

4WD indicator

park brake indicator



I would expect to malfunction. If all of those work properly, it is likely not a ground problem, but a CCD Bus problem. You mentioned in your first post that the park brake indicator was lit, so that sounds like the grounds are ok, but there's two grounds - that throws another variable into it.



It looks like that bus goes only to the instrument cluster, the airbag , the radio, and the overhead console and the PCM. You might ask yourself if you've done any work in those areas (Rear view mirror, overhead, A-pillar, radio, fusebox areas) and retrace any steps taken there. Good luck!

 

[AggieJustin]

Update...

Well, it's been a week and it hasn't happened again... .



I've checked the connections that I could get to without tearing apart the dash and didn't find anything that seemed loose.



Right now, I'm hoping that when the dealer went back and rechecked all those connections that they fixed the loose connection without realizing it.



I had found that TSB and pointed it out to them. They said since it was a '99 that it didn't really apply, but that they would check it out. They said they were at a complete loss. He suggested that it could possibly be a problem within the PCM, but he wasn't ready to start throwing parts at the problem (and I wasn't ready to pay for a PCM just see if it MIGHT be the cause).



So for now I'm hoping that the problem is resolved



Thanks for all the help, this is definitely a post going into my archive for the future.



JM