Speedometer Issues - Sensor & Pigtail Replaced

[levelbest]

Hey All:

2003 Jeep Liberty is having what is a common issue with our trucks, the speedometer is working intermittently, sometimes falls dead, sometimes bounces, sometimes works. Truck would occasionally stall - which I understand can happen when it's not getting signal from the speed sensor.

Took it to our shop and they replaced the wiring pigtail and the speed sensor at the rear - thought they had the problem solved.

Got it back - still had the issue.

They were then convinced as we that maybe an aftermarket alarm system that was tied into the BCM was causing problems (we also have issues with loosing the radio presets and with the jeep occasionally not starting until you pressed the lock/unlock a couple times).

So, we had the after market alarm removed. They tested - and thought it solved the problem.

Drove it for a day and the speedometer is bouncing again. Radio presets were lost again.

Battery is still starting the car so I don't think it's that + alternator was replaced about 6 months ago as well.

What the heck could be going on? Of course there is a possibility the new sensor or wiring pigtail are defective - or that while splicing in the new wiring that they didn't remove enough of the old wiring but.... what else could it be?

Starting to get annoyed chasing this problem. :icon_confused:

 

[Billwill]

Hey All:

2003 Jeep Liberty is having what is a common issue with our trucks, the speedometer is working intermittently, sometimes falls dead, sometimes bounces, sometimes works. Truck would occasionally stall - which I understand can happen when it's not getting signal from the speed sensor.

Took it to our shop and they replaced the wiring pigtail and the speed sensor at the rear - thought they had the problem solved.

Got it back - still had the issue.

They were then convinced as we that maybe an aftermarket alarm system that was tied into the BCM was causing problems (we also have issues with loosing the radio presets and with the jeep occasionally not starting until you pressed the lock/unlock a couple times).

So, we had the after market alarm removed. They tested - and thought it solved the problem.

Drove it for a day and the speedometer is bouncing again. Radio presets were lost again.

Battery is still starting the car so I don't think it's that + alternator was replaced about 6 months ago as well.

What the heck could be going on? Of course there is a possibility the new sensor or wiring pigtail are defective - or that while splicing in the new wiring that they didn't remove enough of the old wiring but.... what else could it be?

Starting to get annoyed chasing this problem. :icon_confused:

There is no reason the truck would stall due to the speed sensor not working!

The fact that you keep losing the radio code would seem to indicate an intermittent loss of voltage somewhere.

You can excercise the cluster...test lamps and move the gauges...by holding in the Odometer trip reset button while turning the ignition ON.

This should move the speedometer back and forth but may not prove anything if the fault is intermittant.

When the speedo gauges jumps around does the Temperature gauge and the fuel gauge also act strangely?

Fuse 13 (10 A) on the fuse panel inside the cabin supplies the Cluster and the BCM with +12 volts when ignition is in the Run/Start position.

Fuse 34 (15 A) supplies the Cluster, BCM and the Radio with constant +12 volts.

I would therefore mainly suspect that the fuse 34 circuit may have a loose connection somewhere....start by re-plugging fuses 34 and 13 a few times to clean up any corroded contacts and if that does work then disconnect the battery and re-plug all the connectors on the BCM which is basically on the rear side of the internal fuse panel.

You can download the 2003 Jeep KJ Service Manual here...includes all the circuit diagrams. What I have stated above is from the 2002 circuit diagrams..the 2003 diagrams I know are basically the same but do have some differences in parts.:hmm:

Index of /manuals/Jeep/KJ

 

[levelbest]

When the speedo gauges jumps around does the Temperature gauge and the fuel gauge also act strangely?

Nope, it's only the speedometer that we've noticed.

On the stalling - the correlation was mentioned when I was searching for solutions to this problem. Hasn't happened recently though.

Anyway - will check the fuses you mention - though if it was a fuse problem that supplies the cluster, wouldn't the whole cluster have issues, especially if the speedo just goes dead for a few seconds or more?

 

[Billwill]

Nope, it's only the speedometer that we've noticed.

On the stalling - the correlation was mentioned when I was searching for solutions to this problem. Hasn't happened recently though.

Anyway - will check the fuses you mention - though if it was a fuse problem that supplies the cluster, wouldn't the whole cluster have issues, especially if the speedo just goes dead for a few seconds or more?

It is hard to say exactly what happens inside the cluster...the circuit diagram only shows the cluster as a "black box" with no details as to what goes on inside it....so it is hard to say if those two fuses will affect the other gauges.

Fuse 34 is common to the cluster, radio and BCM so it is worth a shot but an intermittent problem like yours could be a major problem to solve.
The "always on" voltage that fuse 34 supplies to the radio and BCM is specifically there to maintain the radio code and to keep the BCM with power so you can open/close doors etc. while the ignition is OFF.

If I was tracing this problem I would place a voltmeter inside the cabin and connect it to the lower side of fuse 34, ie. the side that would show no voltage with the fuse pulled out. Then have the voltmeter sitting nearby where you can have a quick glance at it the moment your speedo starts behaving weirdly...I have had to do similar things before on my 2002 CRD!

 

[levelbest]

Ok, so we have the jeep back - and the major speedo issues are gone but are still getting an occasional bouncing.

Son tonite swears that it's tied to having the AC fan on position 2 or 3 and when it is - the speedometer gets wonky. He says it doesn't happen all the time but if he fiddled with the knob on those two speeds it happens. Position 1 seems to be fine. Position 4 can see a little jitter but generally is correct.

So - WHAT THE HECK could this be? Still fuses? Never heard of a fan causing a speedometer to freak out but the shop before we had the after market security system removed said that they saw something similar.

Help.

 

[Billwill]

Ok, so we have the jeep back - and the major speedo issues are gone but are still getting an occasional bouncing.

Son tonite swears that it's tied to having the AC fan on position 2 or 3 and when it is - the speedometer gets wonky. He says it doesn't happen all the time but if he fiddled with the knob on those two speeds it happens. Position 1 seems to be fine. Position 4 can see a little jitter but generally is correct.

So - WHAT THE HECK could this be? Still fuses? Never heard of a fan causing a speedometer to freak out but the shop before we had the after market security system removed said that they saw something similar.

Help.

Seems very weird, the fan speed control simply puts various resistors in series with the ground side of the fan to slow it down....speed 1 has the most resistors in series, speed two has one less resistor in series etc while speed 4 has no resistors in series...the fan goes straight to ground.

The fan may be producing some electrical noise which is interfering with the speedo signal. You have two KJs in your signature...maybe swap out the blower resistor assembly between the two Jeeps...it sits behind the glove box.

When the shop replaced the speed sensor and pigtail did they connect the sensor wiring the correct way around? If the wires are crossed over you get a weaker signal which is more sensitive to external electrical noise.

 

[GranpaQB]

Fix

I've had this problem for a while and fixed it. Before doing anything make sure you clean (sand) the area on the diff where your sensor is located. The sensor needs to be grounded and loses contact because of rust. At least that's what happened to me.

 

[Jeep8731]

Hey All:

2003 Jeep Liberty is having what is a common issue with our trucks, the speedometer is working intermittently, sometimes falls dead, sometimes bounces, sometimes works. Truck would occasionally stall - which I understand can happen when it's not getting signal from the speed sensor.

Took it to our shop and they replaced the wiring pigtail and the speed sensor at the rear - thought they had the problem solved.

Got it back - still had the issue.

They were then convinced as we that maybe an aftermarket alarm system that was tied into the BCM was causing problems (we also have issues with loosing the radio presets and with the jeep occasionally not starting until you pressed the lock/unlock a couple times).

So, we had the after market alarm removed. They tested - and thought it solved the problem.

Drove it for a day and the speedometer is bouncing again. Radio presets were lost again.

Battery is still starting the car so I don't think it's that + alternator was replaced about 6 months ago as well.

What the heck could be going on? Of course there is a possibility the new sensor or wiring pigtail are defective - or that while splicing in the new wiring that they didn't remove enough of the old wiring but.... what else could it be?

Starting to get annoyed chasing this problem. :icon_confused:[/QUOTE

I'm having same problem and I saw somewhere in this forum someone replaced the blower motor resistor because it's circuit went through Speedo?

Looking for that post.

I've done alternator, speed sensor. Hoping to check first cause I'm getting Nichol and dimmed to death.