Gauge Issue

[Lisawhite001]

The gauges on our 2001 Itasca Horizon have been erratic. Oil pressure, speedometer and tach were not working properly. Took to Local Freightliner dealer (thinking a ground issue was the culprit), who ended up replacing Vehical Data Computer, Oil press gauge and Tach. Said problem fixed. All good on way home. Started up yesterday, Speedo registering 55mph sitting still. Any suggestions?

[MUSKYJACK]

I HAD A SIMILAR PROBLEM ON A 96 GM CHASSIS. THE SPEEDOMETER OPERATES ON AC CURRENT PRODUCED BY A SMALL AC DEVICE ON THE TRANSMISSION.IF THE DIODE IS BAD ON THE BELT DRIVEN ALTERNATER ON THE FRONT OF THE ENGINE A SMALL LEAKAGE OF AC VOLTAGE WILL GO THRU THE ELECTRICAL SYSTEM WHICH WILL CAUSE THE SPEEDOMETER TO REACT.THERE SHOULD BE NO AC VOLTAGE COMING OUT OF THE ALTERNATER WHEN THE ENGINE IS RUNNING. AN ELECTICAL TOOL LIKE A FLUKE SHOULD BE USED TO DIAGNOSIS.SET THE FLUKE TO AC VOLTAGE, PUT ONE WIRE TO GROUND AND THE OTHER WIRE ON THE OUTPUT WIRE, THERE SHOULD BE A ZERO READING IF EVERYTHING IS OK. ANY READING WOULD INDICATE A BAD DIODE IN THE ALTERNATER. GOOD LUCK

[MUSKYJACK]

A

[Lisawhite001]

Thank you all for the input. Will let you know what we find out. Going to be looking into all your suggestions this Saturday. Sure Appreciate it.

[Canadian_Rainbi]

Similar problem with our 2002 Itasca Horizon several years ago. Faulty connector behind the dash. Easy to access-just remove the beige plastic cover that surrounds the top of the instrument cluster, back up monitor, radio etc.

You might be as lucky as we were.

[sdianel_-acct_c]

Our volt meter was erratic. We found a loose connection under the dash. We have '04 Country Coach.

[fcooper]

Your system is normally reliable, but can be a real headache to sort out and find problems. Your problem sounds like a wiring problem where a multi-pin connector is not making good contact on one or more pins, but of course I'm guessing.

The engine and transmission computers (along with a few other sensors) feed data to the Vehicle Data Computer. The Vehicle Data Computer then feeds data to the instruments on the dash.

You can find several postings on the Freightliner Owners forum on IRV2. Reading these postings may help you a little.

Two suggestions:

1. Call the Freightliner Help Desk: 1 800 385 4357. No charge and they will help you sort this out. You will need to have the last 6 digits of your VIN number available when you call.

2. If you want knowledge and troubleshooting info about your system, download and read Freightliner Service Bulletin SB 54-12. You can download from the link referenced below:
Freightliner SB 54-12

Good luck in solving your problems.

Fred