This weekend my truck began having a strange electrical issue with the dash. When I turn on the key the lights on the guage panel light as normal, then after a few seconds they all go out except the "air bag" light, then the "security" light comes on. After about 10 seconds the "check engine" light comes on and the chime sounds. When this happens the guages all stop working, but the lights stay on. There are no CEL codes being thrown. I have checked fuses and the grounds and all appears to be good. Dash lights and all switches seem to function normally. Anyone experience anything similar with a solution? Any help appreciated.

 

i would blame the ignition switch, first. i have had that trouble with a 1982 ram, knocking out the A/C. i finally put a relay in the circuit, to take the load off the ign s/w. it wasnt easy, but worth the trouble. be sure and label the new wiring, that to is worth the trouble

 

do a cluster test. hold in the trip rest button, then turn the key on to "run". do not start it. release the button when it says test in the odometer. it will go through all the lights, and the needles on the cluster. see what moves or doesnt move and note. it could be your ctm or cluster.

 

Thanks McNasy I'll give that a try.

 

McNasy, I followed your instructions. None of the needles moved at all. The "Air Bag" and "security" lights came on, then "air bag" light went off. The "security" light stays on. The following numbers appeared in the mileage window. I am assuming they are some kind of codes, but have no idea what they mean. Don't have an owner's manual. #900, 920, 921, 940, 950, and 999 all in sequence. I cleaned the battery terminals and engine ground connections, but it didn't affect the issue.

 

I have the codes handy:

900 CCD Bus not operational
920 The cluster is not receiving a vehicle speed sensor signal from the PCM
921 The cluster is not receiving a distance pulse message from the PCM
940 The cluster is not receiving an airbag lamp on message from the ACM
950 The cluster is not receiving an ABS lamp on message from the CAB
999 An error has been discovered

Most of them suggest you start by checking connections to the CCD bus. You should also check all cluster fuses.

 

OODakDan thanks for the codes. I have already checked fuses and did a reset on the PCM. Can you tell me where the CCD bus. is located?

 

The CCD bus is the computer bus that all the modules in your truck communicate via.

You can usually identify it because it's a twisted pair. You'll find the two wires, one is likely white with a black tracer and the other violet with a brown tracer. Those are 2000 colors, 1999 is the same, not sure of earlier.

Check and make sure all the connections are good.

To really diagnose it requires a DRB scan tool, from Dodge. You'd need to see what is happening on the bus.

It can be the cluster, it is a computer itself.

 

Thanks...I'll do some more checking tomorrow when I have more light. Is it one of the boxes under the dash near the steering column?

 

It's a data bus, it runs all over the truck.

I'd start with the cluster, make sure it's seated in the contacts and that they're clean. Then you're going to have to start checking all modules, the Air bag module, central timer, transmission control module, everything.