Electrical question -- sorry for the long post

I have a 1988 thunderbird sport, 5.0L, with the analog (turbo coupe style) gauge cluster. Recently, the gauges started fluxuating (EXCEPT for the speedo, and tach), and the other day, they went completely dead. Only have
the speedo and tach. I took apart the dash, and have completely checked all the wires, and all the fuses in the dash and nothing seems to be bad. All the fuses are good, and I replaced the voltage regulator on the back of the cluster with a spare from another 'bird (Supposedly a good one). Still nothing, but interestingly enough, my amp meter now works!!!(Has never worked since I bought the car several years ago), However, the other gauges still don't work. So, I only have the amp, speedo, and tach.
Anyone have any ideas what to be loking for here??? I'm completely clueless. Could a bad alternator (Not enough output) do this? are there any connections other than the back of the cluster? fuses, diodes, fusable links hidden throughout the dash I need to find?
Thanks for any help!
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Christopher Wall opined in

Well.. it would be nice if you checked it out with a multimeter or test light to see if power was getting to the IVR..
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Actually, I did check out with a multimeter, but mainly for continuity. I don't know what voltages I am supposed to get from each wire, or the resistance values on the IVR. Depending on how I placed the leads (2 connectors, the small pin, or the piese of foil sticking out) I could get 60ohms, around 10-12ohms, .03ohms, or a random fluxuation.
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Christopher Wall opined in

Well... you should see 12v, average of 5 volts - ticking- and 0 volts all with respect to frame ground. Ohms mean nothing to anyone
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Ok, I'll get back to checking after work then..........any ideas as to what else, if anything I need to start looking for?
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the OHM meter was never designed to be used as a device to find electrical problems. The only use for an OHM meter is checking the resistance of a component to make sure it is in the proper OHM range. You should be checking your circuit live and using your volt meter. The meter should have a DC accuracy of .05% or better and look at the voltage drops across the circuit. The reason for this is that even a small increase in resistance ( one that you would never see on a meter ) will cause a malfunction on a circuit. The resistance will be in range, so you will never see it, but the voltage drop will be very obliviously out of range. Example on a 12 v DC circuit after the load you might expect too see a voltage reading of .05 volts; but with a bad ground the voltage reading might be 2 volts or higher. If you were too check the resistance on the ground it may very well be in proper range.
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