Toyota Repair: Speedometer, combination meter, haynes manual

Question
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Followup To
Question -
Hi Ted:

I have a 94 corolla.  The speedodometer stays at zero mph until the car reaches about 50 mph.  then it shoots up to 70mph, but no higher or lower.  When the car slows down the speedodmeter drops back to zero when the car reaches about 40mph.  It never registers the correct speed.  I have measured the voltage on the connecter (unplugged from the speed sensor) with the ignition on and got the correct voltages (per haynes manual).  Is this a speed sensor problem?  Or could it be the combination meter assy in the dash board?
Answer -
The most common problem is the speed sensor in the transmission, this condition should also turn the check engine light on and trigger a failure code, can you let me know what the code is?
If not, try replacing the speed sensor.

Ted:

There is no error code.  I tested it and the check engine light does not blink.  I replaced the VSS with no change.  The cruse control works just fine.  I tested its accuracy with another vehicle running along side and it set to various speeds ( 35-65 MPH).  Which I assume excludes the ECC and the Cruse control circuits.  Some times the speed registers correctly (usually when the passenger compartment is cold).  I have also noted the temp gauge now reads low all of the time.  I think this all leads to a bad combination meter.  Can you help me?

Answer
Yes there is a problem with the combination meter, it may be that there is  a loose screw or burned out segment on the PC board, the most common cause is the speedometer itself, the next step would be to remove the speedo combination meter and visually inspecting the printed circuit board, if it looks good try replacing the speedometer.