Why does my speedo, heat gauge fuel consumption meters on my honda civic 1996 not working, sometimes when i opens my electronic windows all the meters going on, but now all of them are down

these electronic instrument panels are very delicate so great care must be taken when working on them , make sure all wire connectors are pushed fully home , check at the rear of the fuel gauge for signs of corrosion ,burning ,etc in the printed circuit board , if nothing visable either it is faulty or not compatable , either way will need to be inspected by a auto electrician

most old cars have a speedo cable.
is the odometer dead too. (we need that answer now)

there are 3 class evolutionary systems.
cable
electric sender to cluster
and sender to PCM and PCM drives cluster.
but honda does this on diffr, dates than most cars. (i learned)

so lets do that. we login to alldata.com and look , so can you at any time,
once a month i do random cars.
what engine, sometimes this varies by engine, and trans.
neither stated so Ill toss coin each time.
a/t trans.
1996
has electronic (hall) speed sensor VSS and runs
engine, cruise. odometer and cluster.

the 96 has no speedo cable, and works in modern mode, very advance for this time
also any scan tool on earth fits the PCM scan port
and if VSS is dead, it tells you that with a DTC , vss dead.
saving all that work wondering why it dont work.
see/?
PCM must see it work
and cluster
and cruise
if only cluster fails, and both speedo and odometer then its bad.
if only speedo fails but not odometer , then speedo meter is bad.
its that easy.

It's a common problem with the civic's, the speedo is bad, you can try findind one in the bone yard but it may be bad to, the dealer is expensive, In my 95 civic I turn on my tom tom and it has the speed on it, all the other gauges work fine, the odometer will work fine, just the speedo.

could just be the sensors so check them out with a automotive meter for feed to the tank gauge and then jack car up read for a low voltage output from the speed sensor and if they have power and appear to work then its a new speedo head --- ouch--- expensive

You just have a bad vehicle speed sensor, has three wire's going to it, sit on top of transmission between transmission and fire wall on top of transmission, held on with a 10mm bolt.Depending if it's manual or automatic transmission the part will cost any where between $70.00 and $160.00.Hope this was very helpful.

Its very probably a bad circuit board behind the Rev guage and Speedo. Before you replace it check that the wiring harness is connected firmly.

Souds like the speedo cable / speed sensor has come loose at the back of the gauge cluster. Common problem easily fixed. Make sure it clips in fully next time.

There is 2 harnesses near the bottom of the steering column that you should check. Also change the block fuses in fuse box.

More likely to be the speedo drive in the transmission or a faulty speed sensor that is electronic i would be guessing here as 98 was the change over year for civic so it depends which transmission is fitted. Don't rip the dash to pieces just yet as i'm guessing this will just create more trouble. Steve Baldam in the UK

What the previous owner told you could be correct(that is 33mpg), B16A1 Vtec engine were made for power and fuel efficiency. Your clutch upgrade would not affect your fuel consumption unless you feel anything slipping during acceleration. I say you give your engine a good tune up and compare the milage again.