Where is the vehicle speed sensor for a 1994 vw jetta? Speedometer in new (used) instrument cluster doesn't work just like the original unit didn't work.

Take it to a qualified repair shop that knows how to diagnose these problems . Replacing parts is not the way to do it . Not knowing how this works an having a factory scan tool to view VSS - vehicle speed sensor input to the PCM / ECM - engine computer an data to the instrument cluster microprocessor over the class 2 serial data bus ( network ) You may never fix it . You have the cluster fixed ???? It's not the cluster , checking data with a professional scan tool an checking for codes in the instrument cluster . Not the engine OBD 2 code's .
Speedometer
The speedometer is an analog gauge that is located in the instrument cluster. The VCM/PCM sends vehicle speed pulses to the instrument cluster on a designated circuit.
The speedometer system consists of the instrument cluster, vehicle speed sensor (VSS), PCM/VCM and related wiring. Repairs to the instrument cluster can only be performed by an authorized instrument cluster service center.
The PCM/VCM converts the analog output from the vehicle speed sensor to a digital signal containing 4,000 pulses per mile (PPM) for the instrument cluster. The PCM/VCM is matched to the final drive and tire size of each vehicle. If the final drive or tire size is changed for any reason, the PCM/VCM must be updated in order to match the new final drive or tire size. If not, the signal will not be accurate for proper speedometer/odometer operation. An incorrect signal can affect the antilock brakes and the cruise control systems.
The VSS is a permanent magnet signal generator that sends an analog signal proportional to the propeller shaft speed to the PCM/VCM. The VSS mounts to the transmission tailshaft extension housing on 2-wheel drive models and the transfer case output shaft housing on 4-wheel drive models.

Properly support the vehicle so that the wheels are off the ground. Refer to Lifting and Jacking the Vehicle in General Information.
With the scan tool select Powertrain, Engine Data, and Data in order to monitor the vehicle speed.
Start the engine. Place the transmission in gear and the wheels spinning.
Compare the vehicle speed on the scan tool to the speed displayed on the speedometer.
Does the scan tool agree with the speedometer?

Inspect for a speed input signal to the cluster by backprobing with a J 39200 digital multimeter (DMM).
Select the AC Voltage scale then select frequency.
Measure between the vehicle speed signal and ground.
Does the frequency measure within the specified range?
18-25 HZ (at 20 MPH)

Why ? speedometer not working ? Does the vehicle shift correctly ? The VSS - vehicle speed sensor is an input to the PCM - engine computer > Speed info is sent from the PCM to the microprocessor in the instrument cluster over the class 2 serial data bus . 2003 - 2006 GM vehicles had bad step motors in the instrument cluster . Step motors control gauge position. The VSS is located on the transmission case Vehicle Speed Sensor (VSS)
Lower right rear of the engine compartment, mounted to the right side of the transaxle.

Speedometer
The instrument panel cluster (IPC) displays the vehicle speed as determined by the powertrain control module (PCM). The PCM converts the data from the vehicle speed sensor to a 4000 pulses/mile signal. The IPC uses the vehicle speed signal circuit (4000 pulses/mile), class 2 message from the PCM in order to calculate the vehicle speed. If the IPC detects a malfunction in the vehicle speed signal circuit from the PCM, the IPC uses the class 2 message from the EBCM, indicating the vehicle speed as a backup. If the speedometer reaches (108 mph) the fuel with shut-off, and it will turn back ON when the speedometer is at (106 mph). The speedometer displays either miles or kilometers as requested by the activation of the English/metric button on the driver information center (DIC). The associated indicator (km/h or mph) illuminates.

Did you have it check for DTC'S - diagnostic trouble codes ?
Speedometer
The speedometer is an analog gauge that is located in the instrument cluster. The PCM/VCM receives an analog input from the vehicle speed sensor and converts it to a digital signal containing 4,000 pulses per mile (PPM) for the instrument cluster.
The PCM/VCM sends this digital output (4,000 PPM) to the instrument cluster on a designated circuit. These pulses can be measured in Hertz (Hz) using a digital multimeter (DMM) on the AC scale. The PCM/VCM calibration is matched to the final drive and tire size of each vehicle. If the final drive or tire size is changed for any reason, the PCM/VCM must be updated in order to match the new final drive or tire size. If not, the signal will not be accurate for proper speedometer/odometer operation. An incorrect signal can affect the antilock brakes and the cruise control systems.
The speedometer system consists of the instrument cluster, vehicle speed sensor (VSS), PCM/VCM and related wiring. The VSS is a permanent magnet signal generator that sends an analog signal proportional to the propeller shaft speed to the PCM/VCM. The VSS mounts to the transmission tailshaft extension housing on 2-wheel drive (2WD) models and the transfer case output shaft housing on 4-wheel drive (4WD) models.
Repairs to the instrument cluster can only be performed by an authorized instrument cluster service center. DTC P0502 Vehicle Speed Sensor (VSS) Circuit Low Input and DTC P0503 Vehicle Speed Sensor (VSS) Circuit Intermittent in Automatic Transmission - 4L60-E
- DTC P0500 Vehicle Speed Sensor (VSS) Circuit in Engine Controls - 4.3L Important: If the instrument cluster is completely inoperative, refer to Instrument Cluster Inoperative .
Install a scan tool.
Raise the vehicles drive wheels. Refer to Lifting and Jacking the Vehicle in General Information.
Start the engine.
Place the transmission into drive for automatic transmission and third gear for manual transmission.
Compare the displayed vehicle speed on the Instrument Cluster with the monitored speed on the scan tool.
Does the vehicles speedometer and the scan tool both display 0 km/h (0 mph)? You really need a Factory scan tool or equivalent to check this . The VSS is an input to the PCM/VCM . engine computer . You can test with a DVOM - digital volt ohm meter , for signal to engine computer .
I know most people don't like hearing this , but I suggest you take it to a ASE certified repair facility .

Speedometer
The speedometer is an analog gauge that is located in the instrument cluster. The PCM/VCM receives an analog input from the vehicle speed sensor and converts it to a digital signal containing 4,000 pulses per mile (PPM) for the instrument cluster.
The PCM/VCM sends this digital output (4,000 PPM) to the instrument cluster on a designated circuit. These pulses can be measured in Hertz (Hz) using a digital multimeter (DMM) on the AC scale. The PCM/VCM calibration is matched to the final drive and tire size of each vehicle. If the final drive or tire size is changed for any reason, the PCM/VCM must be updated in order to match the new final drive or tire size. If not, the signal will not be accurate for proper speedometer/odometer operation. An incorrect signal can affect the antilock brakes and the cruise control systems.
The speedometer system consists of the instrument cluster, vehicle speed sensor (VSS), PCM/VCM and related wiring. The VSS is a permanent magnet signal generator that sends an analog signal proportional to the propeller shaft speed to the PCM/VCM. The VSS mounts to the transmission tailshaft extension housing on 2-wheel drive (2WD) models and the transfer case output shaft housing on 4-wheel drive (4WD) models.
Repairs to the instrument cluster can only be performed by an authorized instrument cluster service center.

Diagnostic Aids
• An intermittent in the vehicle speed sensor (VSS) circuit may cause an inaccurate speedometer. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
• Check for the following DTCs:
- DTC P0502 Vehicle Speed Sensor (VSS) Circuit Low Input and DTC P0503 Vehicle Speed Sensor (VSS) Circuit Intermittent in Automatic Transmission - 4L60-E
- DTC P0500 Vehicle Speed Sensor (VSS) Circuit in Engine Controls - 4.3L
Step
Action
Value(s)
Yes
No
1
Did you perform the Instrument Cluster Diagnostic System Check?
--
Go to Step 3
Go to Diagnostic System Check - Instrument Cluster
2
Important: If the instrument cluster is completely inoperative, refer to Instrument Cluster Inoperative .
Install a scan tool.
Raise the vehicles drive wheels. Refer to Lifting and Jacking the Vehicle in General Information.
Start the engine.
Place the transmission into drive for automatic transmission and third gear for manual transmission.
Compare the displayed vehicle speed on the Instrument Cluster with the monitored speed on the scan tool.
Does the vehicles speedometer and the scan tool both display 0 km/h (0 mph)?
--
YES - Go to Step 4
NO - Go to Step 3
3
Does the vehicles speedometer approximately agree with the scan tool display?
--
Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
Go to Step 4
4
Turn OFF the ignition.
Disconnect the in line connector C101.
Turn ON the ignition.
Test the vehicle speed output (4K) circuit voltage from the in line connector C101 (female side of connector) to a good ground using the DMM J 39200 . Refer to Circuit Testing in Wiring Systems.
Does the DMM display a voltage greater than the specified value?
9.5V
YES - Go to Step 8
No - Go to Step 5
5
Turn OFF the ignition.
Remove the instrument cluster. Refer to Instrument Cluster Replacement
Test the continuity from the vehicle speed sensor signal (4K) circuit at the instrument cluster electrical connector to the in line connector C101. Refer to Testing for Continuity in Wiring Systems.
Does the DMM display continuity?
--
YES - Go to Step 6
NO - Go to Step 10
6
Test the continuity from the vehicle speed sensor signal (4K) circuit to a good ground. Refer to Testing for Continuity in Wiring Systems.
Does the DMM display continuity?
--
YES - Go to Step 11
NO - Go to Step 7
7
Test the instrument cluster harness connector for a poor connection to the instrument cluster. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
YES - Go to Step 17
NO - Go to Step 16
8
Turn OFF the ignition.
Disconnect the PCM/VCM harness connector which contains the vehicle speed sensor signal circuit. Refer to Powertrain Control Module Replacement/Programming in Engine Controls - 2.2L or VCM Replacement/Programming in Engine Controls - 4.3L.
Test the continuity of the vehicle speed sensor signal (4K) circuit from the PCM/VCM harness connector to the in line connector C101 using the DMM J 39200 . Refer to Testing for Continuity in Wiring Systems.
Does the DMM display continuity?
--
YES - Go to Step 9
NO - Go to Step 12
have you ever used a diagnostic trouble flow test chart ? Let me know if you make it this far and then I will send the last 9 steps . It's either a wiring problem or instrument cluster or PCM is bad . And if the PCM is replaced it will need progamming . Dealer only .

if the odometer is working then the problem is with the speedometer head unit as the odometer gets its information from the same source as the speedometer. you can have the speedometer head checked and fixed if its fixable.

What sensor is new , vehicle speed sensor (vss) ? That's not how it works ! The speed sensor is an input to the engine computer ,from the engine computer it is sent to the instrument cluster over class 2 or UART serial data bus which ever this has ! The gauge it self is bad or actually it's the stepper motor that is bad ! How to Fix GM Speedometer Instrument Lighting

There is no fuse just for the speedometer . There are main battery supply fuse's for the instrument cluster . If the speedometer isn't working i'd look for VSS - vehicle speed sensor not working or the instrument cluster needs replacing , not a fuse . Your best bet , have a qualified repair shop check it out .

The speed sensor that is under the trans. mount on the driver side sends the shift points to the computer telling it at what point to shift. The sensor that actually controls your speedometer is in the back near the firewall. It is tall and should have a silver heat shield over it. However, the problem that you have described sounds more like an electrical short or a wire grounding out somewhere. I would check for wires getting pinched under the steering column in the dash since things quit working when you are turning. Also check the wiring behind the instrument cluster. Elecrical problems can sometimes be complex and hard to find but with some due diligence they can be solved. Hope this helps.

Either you have a broken wire some where from the speed sensor to the cluster or you have connector at fault, the one which hookup the dash cluster to the main wire bundel. Check the connector, maybe a pushed back pin !!

sounds like vehicle speed sensor i had to replace instrument cluster on my civic