Trying to diagnose an issue for a friend of mine for his S4 Vert.

His gas gauge and water temp gauge read unusually low. These unusual low reading started over a year ago. Now on a full tank the gas gauge barely gets over 3/4 and the temp gauge barely gets above the first marking when fully warmed up.

We thought the temp reading might be as a result of a Thermostat stuck wide open. But after replacing it the gauge still behaved the same.

I know they are both part of one module as we've swapped in several different modules. But all behave the same.

Should we be checking the grounding connection of that module to the gauge cluster circuit board? Other ideas or suggestions to check out?

Thanks

 

Check your sending units and the wiring between them and the cluster.

 

That is on the list to do. But odd that the too low readings happened at the exact same time. It just seems it should be something about connections to the module other than the sending units.

 

Then start with the cluster.
The "motherboard" is conveniently located on the outside, maybe something will be obvious.

 

Following up, absolutely nothing physically looked wrong with the faulty cluster. No burn marks and no cracks on the circuit board, connections on the plugs were clean and solid, etc. Swapped out gauge modules from a used cluster, same problem. Checked resistance at key points that power the gauge modules, all checked out.

So we went ahead and replaced the cluster with entire used one, and that fixed the problem. So cause of the problem remains unknown but problem solved.