Chrysler Repair: gauges wont come on/transmission stuck in limp mode, dash guages, chrysler new yorker

Question
1994 chrysler new yorker none of the dash guages will come on when i start my car and when that happens the tranny stay stuck in limp mode. when all the dash guages are on the car runs great.  once in a while the car will jerk when i am driving down the road also.  i have checked all fuses and replaced ignition switch.  also if the guages are not on all the sudden they will pop on and the car shifts out of 2nd into drive. any advice would be great.  i have asked you about this before and did check fuses and replaced the switch like i said.  thanks linda

Answer
Hi Linda,
It is pretty clear to me that the problem involves the digital communitation system that connects together the engine/transmission/body computer/instrument cluster/airbag module/displays/etc. There are about 10 different modes of failure which can be detected and specified by means of a Chrysler Diagnostic Readout Box II or similar device from the early 1990's.
A Chrysler dealership would have such a device, or if you happen to be in Northern California I have one. Once you have the diagnosis of which failure mode is present the repair can then be affected.
The only simple possibility is that you have a flaky fuse that powers the digital system. Fuses 14 and 17 in the box behind the left end-cap of the dash are needed to operate the system. So all I can suggest that you do with your voltmeter at this point is to check, when the problem is present, that both of those fuses are getting 12V when the ignition is 'on' and that 12V is present on both sides of each of those fuses. You might find that is not the case due to a flaky fuse in which case you would replace that fuse. If that proves to be OK, then find the blue connector with 6-wires located under the dash to the right of the steering column. Then measure the voltage on the white/black and on the violet/brown wires again with the ignition in the 'on' position and you are having the problem. It should be about 2.5V for each wire. The one voltmeter lead would be attached to the wire I mentioned and the other to any shiny metal chassis surface nearby. Again, this too would be checked when the gauges done't work. If the voltmeter tests pass, then a readout via the DRB II will be necessary to identify what is wrong with the digital data bus.
Roland
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