1996 Audi A4 2.8l fuel and temperature gauges not working,what could be the cause?

If the tail lights, low fuel light, temperature gauge, and fuel gauge are not working, there could be several possible causes:

1. Blown Fuses: Check the fuses for the tail lights, low fuel light, temperature gauge, and fuel gauge. If any of these fuses are blown, replace them with a new one.
2. Loose or damaged wiring: Inspect the wiring for the tail lights, low fuel light, temperature gauge, and fuel gauge. Look for any loose connections or damaged wires. Repair or replace any damaged wires and ensure all connections are tight.
3. Faulty sending units: The low fuel light and fuel gauge are connected to the fuel sending unit in the gas tank. The temperature gauge is connected to a temperature sending unit on the engine. Check these sending units for faults, and replace them if necessary.
4. Faulty instrument cluster: The instrument cluster itself could be faulty, causing the temperature and fuel gauges to not work. A qualified mechanic can test the instrument cluster to see if this is the issue.

It's also possible that the trike has a separate electrical system for the tail lights, and that this system is malfunctioning. A qualified mechanic can test the trike's electrical system to determine the cause of the issue.

Check your coolant level, if it's too low it won't come in to contact with the temperature sensor.

some times after market senders read hotter if there not quiet the same value

Hope you used factory sender. Aftermarket senders have contact problems. Audi updated their senders to gold contacts to improve performance. Moving it by hand may force good contact as opposed top free floating in tank

I’m happy to assist further over the phone at https://www.6ya.com/expert/howard_977676954994c5b2

The cluster is defective.

This problem is due to a failure of the electronics that drive these gauge displays. What must be done is to have the instrument cluster removed from the car and sent out to a factory approved repair center for repair and upgrades. This is a common issue on the van

check the fuses. they are under the back seat just pull up on the lower part of the back seat and it will come out. fuse box is on the drivers side. check to see if water is getting in that could be the cause.

Pull the sender wire. Gauge should go all the way cold. Short the sender wire. Gauge should go all the way hot. Replace sender or gauge depending.

THE FUEL FILTER WOULD NOT CAUSE THIS, iI WILL ASSUME FOR THIS SOLUTION YOU HAVE SPARK WHREN YOU HAVE THIS HARD START.
Here are the problems that will cause this problem
1. fuel pressure is bleeding off due to a fialed fuel pump check valve, since to check this u need a special test gauge that runs about $40 it is best to have a local shop do this "Fuel pressure leak down test"
2. The ECT sensor (engine coolant temperature) is defective and not giving the proper engine temperature cold, this causes the fuel injection to supply a lean mixture with the resulting hard start, to check this you need a shop to read the ECT with a special live data scan tool to determine if the sensor is within tolerances for the engine temperature reading it provides to the computer.

How do I locate the sensor on a 2003 A4 1.8L? I see a blue sensor on the right by the firewall, and a green sensor on the left nearer to the battery on the left. Is it possible that I already have a green sensor in my car?