Caravan 1989, 3.0, electrical problem with dash and radio

Hi all, I have this rediculous electrical problem. it is a Dodge Caravan LE 3.0L Overdrive Trans my dash meters missbehave sometimes, and my radio is in mono.
the RPM sometimes falls like the engine is off and somes back when i hit it, or hit a bump. and My coolant temp is flicking side to side, and my oil pressure sometimes goes to low, the Check gages light comes on sometimes. I took it apart, even replaced the RPM gage, This tells me that the RPM is a contact problem somewhere behind the dash, and the others are a short somewhere in the car.
The radio was missing when i got the car, the wires were there, so i soldered the connectors from my other caravan 89 and installed the radio from the other van aswell, it plays in mono and really bad, you can't distinguish what the words are. Could it be that the speakers ar 8ohm and the radio is for 4ohm, what can i do to fix this?
please anyone had experience with wiring. The car is old so i'm thinking it could be a worn wire, the inside wiring is in Ok shape wasn't touched much before.
i like this place, not much activity but no matter, someone is out there with the answer just waiting for the right question to pop up. thanks Ilia
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ok another false alarm, my sigarett lighter was out too, when i traced the problem to a blown fuse, it also fixed the radio, not sure how, probably uses same poser line as the lighter, i'll see if this fixed the dash problem aswell, going for a drive today, let you all know. also after changing the fuse, i have a fault code come up, 12 and 15, i wonder if this is because i too out a couple of fuses to see if they are ok, or this is because my Cat is caput. anyone had experience with trouble code 15? any help will be apreciated, thanks Ilia
snipped-for-privacy@gmail.com wrote:

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wrote:

The code 15 is your vehicle speed sensor, does the speedometer work??
Glenn Beasley Chrysler tech
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wrote:

I have had the dash problem, and this same code 15 in my 87 caravan SE, also a 3l.
I'm guessing when the guages go, the guage lights don't come on, the indicator lights ont he dash do, and work inversly when an indicator is used, as does the high-beam light, and all when the headlghts are switched on. A bang on the left corner, above the left side warning lights section will often fix it. Oh, and most of the guages, including the fuel and temprature go to extremes. Speedo is unaffected however. Oh, and if you have no headlights on, it'll bliink the low voltage warning in time with the turn signals, when they're used.
The code15 seems to come on most times, usually within a mile or two of startng. speedo seems fine, except it always over-reads by about 5mph. (it says 40, you're doing 30)

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thanks for your replies, Yes my spedometer works, so i'm not sure why code 15 still persists. I got my radio, sig lighter and horn to work, they all use same fuse apperantly, which was blown. but the dash, man it is like every car has it's own personality. I took mine apart back then and looked at the PCB, no cold solder or brocken solder joints, all connections are snug. even changed my RPM gage, still same thing: rpm falls to 0 and comes back when i hit it or the car hits a bump in a certain way, the oil pressure goes below Low when car is well wormed up and i stop at lights, the coolant temp gage flicks side to side almost all the time, exept at acceleration(which indicates a bad connection somewhere, cuz the acceleration creates higher voltages/amperes and it fixes the problem). I don't know maby i should let it be. and hope to come across it when i have to fix something else. Can you guys confirm if the oil pressure is purely due to the gages only and not actual indication of a low pressure? thanks for your replies. Ilia
flobert wrote:

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