Freightliner Instrument Clusters

There are many different reasons why your instrument cluster or gauge might not be working. The failure could affect the entire instrument cluster, or an individual gauge. Some gauges may be part of a single Instrument cluster. Other gauges may be mounted in the dashboard individually. The reasons for a failure may include:

• Relay or Fuse
• Wiring Problem
• ECU or Sensor Failure
• Age or Wear

Inspect to see if some or all of the gauges are not working. If the entire instrument cluster is not working, check to see if it is getting power:

1. Locate the fuse panel in the cab and check for a blown fuse or a defective relay.
2. Use a multimeter or voltage tester to check both sides of the fuse. 
3. If voltage is present on only one side, replace the fuse. If the fuse blows again, there's a short somewhere in the wiring.
4. Check for power on both sides of the solenoid.
5. If voltage is present on only one side, replace the relay.

If the fuse blows again after replacing, there could be a short in the wiring. The fuse blows to protect the instrument cluster from damage caused by a short or high current. If the fuse and relay are okay, there could be an open in the wiring. Check the wiring as follows:

1. If the fuse is okay, remove the instrument cluster and check the supply voltage at the connector.
2. If the correct voltage is present, check the ground circuit at the instrument cluster connector.
3. If there is no voltage, check for a broken wire. 
4. If power and ground are okay, the instrument cluster should be replaced.
5. If the fuse is blown, pull the fuse out and check for a short at the instrument cluster connector.
6. Identify wiring damage and repair as needed.

If only some gauges are working, there may be missing signals from the ECU (Electronic Control Unit) or sensor:

1. Some instrument clusters may store trouble codes. If you have access to a scan tool, check for stored DTCs (Diagnostic Trouble Codes). 
2. Determine how a gauge receives its signal and check the corresponding ECU, sensor, or wiring. 
3. If no problem is found, the instrument cluster should be replaced. 
4. If the gauge is separate from the instrument cluster, replace the affected gauge.

Fuses are in the instrument cluster. The fuses sit between the power supply for the cluster and the cluster itself. There's usually a fuse box underneath the dash on the driver's side. Some trucks have one fuse dedicated to the instrument cluster. In other trucks, there's one fuse dedicated to each gauge, or to separate sets of gauges.

The purpose of having a fuse in the wiring system is to protect the instrument cluster and the sensors or ECU. If there's a short somewhere in the wiring, the fuse blows. In doing that, the fuse prevents the part on the other end from getting damaged. In other words, the fuse cuts power to the other part - and that means your cluster won't illuminate.

Your first option should always be to replace the instrument cluster. It's because a quality replacement instrument cluster is already calibrated and tested. That means if you install a replacement instrument cluster the right way, you'll know that it works.

You don't have that same assurance when you try to repair the cluster yourself. When you do it yourself, you don't have a way to test your instrument cluster. If you're lucky, the instrument cluster will work right, but you won't know it until you put everything back together. If you're not so lucky, you'll put everything back together and then find out that the instrument cluster either:

• Works right for a while and then fails again
• Doesn't work at all

The best way to save yourself time and money is to replace your instrument cluster with a quality one from a reputable company (like ISS Automotive). Here is a more detailed article about repairing or replacing your instrument cluster.