1995 Dodge Caravan Speedometer Stops Working At Times

  • 6 CYL
  • FWD
  • 12,700 MILES
I have a 1995 Dodge Caravan I seem to be having some sort of electricla promblem. When traveling down the highway out of the blue my tachometer will start rapidly move up and down from 2 to 7 up and down. Then speedometer will stick at whatever speed I am traveling at. My volt/amp guage will rapidly jump up and down from 14 volts down to the bottom on 8 volts and back to 14 volts. This will continue untill I shut my engine off for a few minutes and restart. Then once I restart the engine the speedometer wil become unstuck and drop done to 0. Once I put it in gear and drive away everything is fine. Whenever this occurs I never have any check engine lights or service engine soon lights come on. No warnings whatsoever. It might be a week or even a month later till it does it again. Sometimes it may be three to six months. Also my cruise control does not work at all. I hardly ever use it maybe once a year when on a long trip. My Dodge Dealer said they cannot test if for I need to bring the vehicle it in when it is malfunctioning, but by the time it starts acting up and by the time I can get to the Dealer it stops for I have to shut the engine down and restart before I get an apointment set up with the dealership to bring it in. It always seems to happen when the dealership is not open or on a wekend. One mechanic I talked to over the internet chat room said it could be the transmission speed sensor another said it was the alternator. I had the engine completely tuned up and serviced at 125,000 and had the transmission oil and filter changed as well. The problem began before I had all this service done to it and continued after have the engine and transmission serviced.
Do you
have the same problem?
Friday, March 19th, 2010 AT 11:35 PM

1 Reply

In 95 3 main computers were tied to gether on communication wires. Body, engine, and transmission. PCM, TCM, BCM, each has self diagnostics. The speedo gets it's signal from the vehicle speed sensor, the tach gets it's signal from the two sensors on the transmission(input and output) the voltmeter is driven by battery charging voltage by the body computer which drives the instrument cluster. If your having problems with any one of the three this could occur. What does the dealer say about the DRBIII they use to read all these systems. There may be a code for a bad TCM or BCM. They have bulletins regarding cluster ground problems also. Have you ever taken it in to the dealer so they can see if any fault codes are present? I think you may have a problem with the instrument cluster itself. A bad circuit board or ground or poweer wire in the connector behind the cluster. This was a common complaint. If I see any bulletins regarding this I'll let you know. Bulletin 08-07-94 Rev. B deals with the plug wires interfering with the input sensor wires causing bad signals, a bulletin 08-77-94 is for vehicle speed sensor problems causing speedometer flucuations the new part number was 4707386. The TCM had problems also bullrtin 08-15-99 is for reprogramming the TCM, which gives tachometer information that is used for shifting and by the BCM for the cluster.
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Sunday, March 21st, 2010 AT 12:20 AM

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