erratic gauges

[adiabatic]

Our 98 12-V truck has the electronic (smart!) dash, and lately the gauges have been acting up. The speedo goes suddenly to max then back to normal, while doing a steady 35mph. The fuel gauge swings wildly but on its own schedule. Any ideas?

 

[Alan Reagan]

Yeah, I can help, but don't have my service manual. There is a wheel speed sensor on the rear axle and I can't remember whether or not that is the speedo or just anti lock brakes. Seems like the speedo sensor is the one on the side of the transmission the more I think about it. Sounds like either a bad connection or the sensor is going bad. Sorry. I'm brain dead this morning.

 

[PMalin]

I had an intermittent erratic gage display once. I took it to 2 dealerships and a small town dealership where they had a lot of local farmers. They had the techs that could fix it the first time. Anyway, they said they found a problem with a ground wire for that circuit. In this case, they had to route it slightly different and so far, (several months) it has been ok.

 

[b.j.oneill]

I have a ???? my water temp gauge is doing some strange things it goes from normal temp it goes up a 100 or so then drops back to normal in about 5 seconds any ideas

 

[illflem]

Usually when more than one gauge messes up it can be traced back to a bad ground. You really need a service manual for your model year to hunt it down.

 

[Alan Reagan]

b. j. oneill, Sounds like your thermostat is sticking.