Nissan Repair: Nissan Terrano Fuel Gauge Problem, nissan terrano 2002, tach readings

Question
I have a Nissan Terrano 2002 fuel gauge problem.  Gauge goes to full when
ignition is turned on, then completely empty as if not registering at all.  Could
it be the fuel relay under the hood?  It sometimes works fine and then some
days not at all!

Also the Rev counter seems to be broken the needle just points straight
down.  is there a way to check the output with a volt meter?
Thanks in advance.
Regards
Simeon.

Answer
Simeon,

The fuel sending unit, in the petrol tank, is defective.  That is the first and best analysis of your problem.  The ignition test is the key to the answer.  The gauges go into self test when the key is turned on.  Since the gauge moves fully and then drops tells me the sender is not providing information.  Also, on the tach (rev counter) you could check this with a scanner that pulls information from the OBDII port under the dash.  If you get tach readings on the scanner then you know your tach is defective.  Now, you could remove the cluster and clean the contacts and reinstall and see what goes on.  In the United States Nissan seems to have a problem with cluster connections.  Many problems are resolved by removing the cluster and cleaning the contacts on both the cluster and harness connector.  I use a pencil eraser to shine up the metal contacts, blow off the eraser dust, and reinstall the cluster.  Works wonders on many clusters.