what do you mean? did they stop working, work now and then, or what is working and what not? if everthing is dead and the truck runs ok, then ckeck the fuses, but im not sure at all it could be PCM related.
There is no fuse just for the speedometer. If the speedometer is not working, you may have a problem in the dash gauges cluster, or a vehicle speed sensor problem.
my 1998 doge ram van, all my gauges are not working
You have to access the gauges by removing the cover. Unless you know what you are doing, you can mess up a lot of things working on the dash.
To remove the dashboard from a 1998 CLK Mercedes Benz, start by disconnecting the car battery for safety. Next, remove the trim pieces surrounding the dashboard, which may involve unscrewing or prying them off. Then, detach any screws or bolts securing the dashboard, including those near the instrument cluster and the air vents. Finally, carefully pull the dashboard away from the frame, taking care to disconnect any electrical connectors for the gauges and controls.
To replace the dashboard lights on a 1998 Nissan Maxima, first, ensure the vehicle is off and disconnect the negative battery terminal for safety. Remove the dashboard panel by unscrewing any visible screws and gently prying it off to access the gauge cluster. Unscrew the gauge cluster, disconnect its wiring, and then replace the burnt-out bulbs by twisting them counterclockwise. Reassemble the cluster and dashboard, reconnect the battery, and test the new lights.
Cluster removal link below: http://www.youtube.com/watch?v=6jXiwgm3bPg
It could, along with the gauges themself and dozens of other causes. A scan tool capable of communication with the body computer and cluster is required to diagnose.
My dash lights went out and the cause was a bad alternator. new alternator fixed the problem
Your speedometer may have failed, or the speedometer cable that connects to the transmission, or the plastic gear in the transmission may be broken.
I had the same problem with my 1998 Dodge Ram 1500. I reseated the instrument cluster and it started working. The whole thing took me 15 minutes and I am not a mechanic. I believe that I removed three screws to enable me to remove the plastic which covers the instrument cluster. I can't remember how many screws hold the cluster down but once you remove them pull the cluster out. It is simply plugged in, and those connections are your problem.
It will have to be removed and sent off for repairs.
No. The spark plug wires have nothing to do with the illumination of dash gauges. Check your fuse box for blown fuses. A blown fuse that corresponds to the instrument cluster will cause that.