Cluster not working

OldSkewlGamer

Little back story. I bought this 97 dakota with the possibility of it just being a blown fuse. As of now i have no gauges working on the cluster. Backlight on the cluster itself works. Getting multiple error codes essentially coming back to no bus code. Ive checked all sensors i can think of under the hood to make sure they are getting 5 or 12 volts. I also have no driver side headlight and low power in D. But i can manually shift down to 1st and 2nd then to Drive and maintain power the whole time but upon stopping and taking off again you can tell its down on power.

thecardoc3

The instrument cluster gets a lot of its data via the communication bus (wire) from other computers on the car. When you see "No Bus" in the odometer then that means the cluster isn't getting that needed information. Testing starts by confirming that the bus isn't shorted to power or ground, and then from there if the communication waveform (10v pulses at roughly 40, 000 bits +/- per second) is readable. The fact that the car runs does prove that powers and grounds have to be correct for the engine control module. The fact that the cluster can display "No Bus" also means that it also has correct powers and grounds.

The factory DRBIII scan tool can help with this diagnostic issue, as can other professional level scan tools. Then depending on what is found, it does take some training and experience with electronics to troubleshoot from there. The one thing that you can do is measure from pin 3 to ground with a digital voltmeter and see how many volts it displays. 10v or higher and any one of the modules has likely lost a ground connection. Close to 0v and something is likely shorting the communication bus to ground. If you see somewhere close to 4v now you really need an oscilloscope to make the measurement so that you can see what is really going on.

You may need the assistance of a technician that is experienced with this kind of diagnostics.