1991 N13 gauges problem

Hi all,
I got a 1991 Nissan Pulsar N13 with gauges problem. Fuel and temp gauges dont work. the fuel is completely dead and the temp takes a while to go up.
I just installed a different used instrument panel but nothing really fixed. I filled up the fuel tank but the gauge only show 1/4 left. and this time the temp is completely dead.

Is this a wiring problem? or just the wiring is old?
Is it difficult to fix it myself?

Thank you!

according to JohnB868washere its a voltage regulator thingie on the back of the cluster....but if you swapped out the instrument panel does that mean its a different regulator? i dunno....

I'm having the same problems with my '89. Seems pulsars wireing is not the greatest, everyone I've ever talked to that hs owned a pulsar has electrical problems. Changing the voltage regulater fixed mine, but only for a couple of weeks. I still haven't been able to find the root cause for it though. I'm guessing there is a short somewhere, but where, I don't have any clue.

i have the same problem with ny 1988 pulsar vector n13, only both gauges are completly dead. i know theres voltage all the way but i am unsure about behind the console.
my main cooling fan does does not kick in even though voltage is detected any ideas.
thanks