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Old 10-11-2014, 02:59 PM
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Speedometer issues

My speedometer jumps by increments of like 20mph, not accurate to the speed I am going. when I come to a stop, it comes down to 20mph and stays there when I am fully stopped. HELP.

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Old 10-13-2014, 05:24 PM
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Re: Speedometer issues

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Originally Posted by Didi View Post
My speedometer jumps by increments of like 20mph, not accurate to the speed I am going. when I come to a stop, it comes down to 20mph and stays there when I am fully stopped. HELP.
Presumably you have a Jeep.
What year, make, model, etc?

Some years had quite a bit of trouble with the circuit board the speedometer is mounted on, where the speedo and dash odo would cut out but the trip odometer in the overhead console would keep working.
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Old 10-14-2014, 08:22 PM
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Re: Speedometer issues

Sorry, 1995 Grand Cherokee Larado
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Old 10-14-2014, 08:30 PM
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Re: Speedometer issues

The '95 uses a cable. There is quite a bit of info at the link below.

https://www.google.com/search?q=95+j...oe=&gws_rd=ssl


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Old 10-15-2014, 05:46 PM
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Re: Speedometer issues

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Originally Posted by bill_de View Post
The '95 uses a cable. There is quite a bit of info at the link below.

https://www.google.com/search?q=95+j...oe=&gws_rd=ssl


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Note, there MAY be some models of 95 that used a cable, but the Limited definitely did not. Google for "1995 jeep grand cherokee jumping speedometer" as the 95 was infamous for bad speedometers or more commonly intermittent ones, where some are so bad they jump around at 0 mph. Some good videos.

There is an electrical Vehicle Speed Sensor at the transmission, which can get moisture in it from crappy design and cheap o-ring. Easy to fix from any hardware store selling o-rings, plus a bit of silicone grease.

That single speed sensor goes produces a digital signal that goes to both the overhead console and the instrument cluster.

If you can see the displays in the overhead console [presuming you have them] changing, that sensor signal is OK.

If the sensor is bad, it is trivial to replace, but a good mechanic would check the signal on the thing.

If the overhead displays related to mileage change, but the speedometer [and usually the odometer] don't, or the speedo jumps, it is most likely the speedometer unit itself or a cracked circuit board in the instrument panel. Unfortunately the part of the speedometer assembly that tends to fail is frequently heat sensitive which is how the cracked instrument panel printed circuitry also behaves.

It isn't that difficult to pull the instrument panel, but there are some screws just behind the windshield that require a very very short or specialized screwdriver to get at unless you pull the windshield. You'd want a factory service manual or equivalent. To have someone else fix it would be expensive as there is a bit of labor involved. The speedometers are available, the instrument panel tends to be a junkyard item, but if you go that route, pick up a speed sensor so you can test it before installing--stick a drill on the speed sensor. You can solder flex wire [cable braid works, as does solder flux remover braid] across any cracks in the instrument panel.

One guy on the internet claimed to have a source for a cheapo part that tends to cause the most spectacular jumping, but I don't recall ever seeing any for sale.

I used a junkyard panel/speedo ... and then traded the jeep.
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