How to fix Rpm and speedomiter not working.

Hello It sounds like you need a new speedomiter cable go to your mech.in your Area im sure they can fix the problem

Is the battery light on?
Or do you have a gauge

check fuse first. (as always)
what is the odometer doing.
caldina?
non here.
my wild guess, no FSM on that.
is:
1: the VSS is dead.
the questions is where is the VSS , vehical speed sensor.
on most cars that depends on engine options and transmission options.

i think? the VSS tells the PCM speed, and the PC drives
KM meter and odometer.
and RPM is PCM input of Crank sensors
so id say fuse, but the odometer questions is more revealing

should be in transaxle i think.

so the only thing not working is the fuel gauge? the odometer , speedometer , and rpm gauge work, but dont light up? if so, does the radio or any other lights illuminate? check your dimmer switch for these issues. please let me know a little more information

LOL! SIMPLE STUFF! FIRST FIGURE OUT IF YOUR CAR HAS AN ELECTRIC SPEEDOMETER OR CABLE DRIVEN ONE. THE ODOMETER IS USUALLY PART OF THE SPEEDOMETER SO IF THE CABLE IS BUSTED OR THE ELECTRICAL CURRENT TO IT HAS FAILED? IT WON'T WORK AT ALL. I BELIEVE A 1990 HAS A CABLE DRIVEN ONE SO JUST TRY REPLACEING THAT CABLE FIRST. U CAN GET IT AT ADVANCED OR AUTOZONE OR A DEALER IF U WANNA PAY OUT THE NOSE.....UR CHOICE.

check wiring behind intake manifold support.

My gas guage, speed odometer and tempiture does not work
The speed odometre is reading 9999999 what should i do

check the fuses?

HI
I had same problem with a 1990 skylark form what I have seen on the net this is problem with the older skylarks. I got one from a junk yard for $45. It was easy to put in. I could have sent the old one out to be fixed but I was told $250-$300. Hope this helps