MECHANICS I have a 99 Jeep Cherokee and the speedometer is not working?

Question

Some days it's fine and the next it's not working again. Sometimes all the gauges stop working. What is going on ? How much cost will the repair be?

Answer 1

There's just too many possible things that could be the problem.

Electrical things are difficult to trace down, however by your description (especially since all your gauges sometimes stop working), it's highly likely that you have a bad grounding wire. The question is which grounding wire is not grounding properly will take some time to figure out.

Did you have any type of work done on the car before this started occurring? (ie was there some mechanical item worked on in the engine compartment?, did you replace a radio?, install speakers?)

If it is a bad grounding wire (and I'm not necessarily saying that it definitely is) Anything that you had done just prior to this starting may give you a key as to where to look for a badly grounded wire.

Other possibilities are a bad speed sensor, but typically this doesn't affect other gauges. Or a bad instrument panel

Answer 2

Although a speed sensor is a possibility, I am leaning more toward a wiring fault, faulty instrument cluster, or possibly a faulty ignition switch.

Did you have any work done specifically inside the Jeep? New stereo, GPS nav, heater core, alarm system, DVD player, or any other work which would involve possibly invasive procedures being performed inside the dash?

All modern vehicles have inductive pickups instead of speedometer cables like older vehicles did. This is because vehicle speed is one of the things the OBD-II computer wants to know (and many OBD-I vehicles too). Also, the cruise control wants a vehicle speed signal as well. Therefore, don't even look for a speedometer cable. You have one (or two) vehicle speed sensors specifically for this purpose (if you have ABS, you'll probably have one in each wheel), most likely installed in the transmission (near the output end) and/or in the rear differential.

If all of your instruments are failing intermittently, then most likely, you're either losing ground or power. It is possible that your ignition switch has a separate contact for instruments, a/c, etc., one for ECU, and one for stereo and accessories, theoretically it is possible for you to have a faulty ignition switch and still be able to drive. The actual layout of the ignition switch varies with vehicle make, model, and year.

If you don't get a MIL (check engine) code, most likely you don't have a problem with the VSS (vehicle speed sensor). Since your ECU looks for this signal, it will most likely complain if it is missing.

It will be a real pain in the afterburner to figure this out and fix it. Intermittent problems always are. Buy the repair manual and break out your DMM (digital multi-meter).

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Answer 3

I had the same problem on mine. If it's just the speedometer and the odometer, then it's most likely the the connector to the engine for those gauges is loose. If you take it to the dealer they'll charge you about $100 for the inspection. Take it to a small auto mechanic and you'll pay about $20.
Worse case is the ECU is acting up. that could cost about $1000-1300 to replace.

Answer 4

Sounds like the instrument cluster is going out. Check for loose connections on the back of it, as well as the wiring system that runs to your ECU. It's likely the instrument cluster though, if other gauges are failing or intermittantly failing. Call your local junkyards to see if they have instrument clusters for your jeep, or if they have similiar year jeep models to yours. They're mostly all universal plugs for the Jeeps, but there's no way to repair a faulty cluster, only replacement.

Answer 5

sounds like you probably have a bad speed sensor, should be one in the tranny and 1 in the rear end, They are not terribly hard to replace and not extremely expensive. should be able to get one from Autozone or the like. I think the one i replaced in my truck cost about 30 bucks

Answer 6

The first thing to check is the speedometer cable to the transmission. It could be loose.