Tachometer / Speedometer Problems:

[sharkssn591]

Backgroound info:
2002 Mountaineer AWD, 4.6l V-8, about 50K miles.

Problem Periodically the speedometer and tachometer quit working:

symptom elaboration:
The tachometer will drop to zero RPM, shortly after the speedometer will no longer rise in indicated speed and will slowly lower, if the dash is tapped the speedometer will lower until it reads zero. If the truck is stopped, the speedometer stays where it was left, upon restat the speedo goes to (is driven to) zero, the tach goes to 1000 RPM (normal) however periodically the tac will drop (and remain) back at zero, if the so the speedometer will not work. If however the tach responds normally the speedo responds normally.

Additional information:
The truck's drivability appears to remain unaffected, (MPG is unchanged, lack of a check engine lite and normal accelleration etc.) cruise control continues to work fine. Generally if the truck is turned off and a wait of more than 30 seconds before restart indications return to normal.. The symptom may or may not retrun, and appears to be more frequent of late.

I assume the speedo and tach are computer controlled, however I do not know which.

Any ideas? thanx in advance.

 

[BrooklynBay]

Open the dashboard, and clean the electrical contacts on the cluster.

 

[sharkssn591]

Thanx, when the weather breaks I'll give it a try.. My initial symptom evaluation led me away from "connections" due to it "corrects itself" if shut it off and restart..thinkinng it was a computer interaction...??

 

[700summitguy]

Ran into a similar problem at the shop today. It was a cracked line in the printed curcuit. Tap the speedo, it would work. Tap again it would quit. Hope this helps.

 

[00XLS]

anyway to fix that ? cracked printed circuit ?

 

[green4WDmonster]

I'm having a similar problem with my speedo. in cold weather it seems to stick. but once the truck's interior warms up, it functions normally. i thought it might be water freezing on the magnet that caused it to stick....but it does it at temps well above freezing. Once temps go over 60 the problem disappears all together. I've already cleaned the contacts and put conducting jelly on them in hopes of improving signal without any change in it's behavior. Any ideas?

 

[IZwack]

Yeah which PCB is this thats cracked?

 

[2002 Eddie Bauer]

Does the explorer have a speed sensor in the rear end or tranny that could go bad?? I have had other cars with similar symptoms and it is always the speed sensor. An easy fix!!

 

[BrooklynBay]

Welcome to this forum! Every year has different locations. Later models use the sensor on the differential.

 

[2002 Eddie Bauer]

does the 2002 V8 model have the speed sensor on the rear differential? If not sure, where can I look to find out??
Thanks

 

[panamexplorer]

Could a fault in the Tachometer cause a rough idle or stall problem, since the sensor feeds information through the pcm?

Anyone?

 

[Runnin'OnEmpty]

does the 2002 V8 model have the speed sensor on the rear differential? If not sure, where can I look to find out??
Thanks

If equipped, the speed sensor will be on the front side of the diff,
high up on the driver's side. It'll have a wiring harness going to it,
and is held in with one bolt. Very easy to change, although you
have to be a contortionist to reach it......

 

[TOMANDPAT]

This is a long shot, but might be worth your time to check out. The cruise control switch on the master cylinder that is the subject of recalls could be your problem. We just replaced the switch on a '99 Windstar that was defective, and had caused the speedometer and odometer to fail. The windstar did not have a tach, if I remember correctly. The dealer will replace the switch for free


Tom

 

[MBeaston]

1995 Ford Explorer 4.0 Automatic My Tach Quit Working And So Did My Speedometer But If I Tap On It The Tach Bounces Off 0 But Comes Right Back To It Just Started Out Of The Blue Any Ideas?