[Fixed] 1997 GMC Sierra Speedometer Problems And Causes!

Riding the 97 GMC Sierra that shows the wrong MPH in the speedo is risky since one is not able to determine the actual speed. In that case, troubleshooting is needed based on the causes.

Here are the main reasons why the 1997 GMC Sierra speedometer problems showing in your car:

  • VSS wire loose or fault in the sensor.
  • Incorrect size tires are added to the car.
  • Trouble codes.
  • The speedo fuse is fried up.

After learning the causes, it’s time to solve the bugs that your car’s speedo is suffering from. Let Me Show You!

1997 GMC Sierra Speedometer Problems And Causes!

Fix 1997 GMC Sierra Speedometer Problems

Depending on the error type, I’ll explain the reasons and then give the solutions so you can perfectly solve the bug without making mistake.

Issue #1: Speedo Stops Working & ABS Light Turns On

This kind of issue sometimes occurs when the speedo refuses to shift into drive while the ABS light pop on. It happens when the VSS (Vehicle Speed Sensor) wiring is loosely wired or the unit itself needs replacement.

The Solution

  • Open the hood of your car.
  • Disconnect the negative side of the battery and then the positive side.
  • Locate the VSS unit. It is located on the tail shaft housing of the passenger side transmission in 2WD or the transfer case (underneath) in 4WD.
  • Wear your goggle and eyewear to ensure safety.
  • Then, inspect the wiring side and tighten out the plug. If it’s okay, then go to the next step.
  • Take an adjustable wrench to hold the unit and loosen it out.
  • Use your hand to simply twist the unit and remove it. Do not use a harsh tool as it can break the speed sensor.
  • Clean the surface if you locate some kind of dust or mouse trap that can also block the path.
  • Insert new VSS that seems good in condition and quality. Be sure to twist it in order to attach it properly. Then, use an adjustable wrench to tighten it out.
  • Put on the plug into the port and be sure it’s nicely inserted.

Issue #2: Unpredictable Swings of Speedometer

A lot of times the speedo can show inconsistent swings where the indicator needle just goes upward to downward or vice versa. This occurs when you insert the wrong size tire into your 97 Sierra GMC which causes the speedo to read incorrectly.

The Solution

  • Check the door jamb to learn about the correct tire size for each tire.
  • Remove your car tires and insert new ones.
  • Grab a calibrator tool for speedo and simply calibrate it.

Issue #3: Incorrect Reading of Speedometer

Has your car’s speedo needle stuck at 80 MPH while you are going in 20 MPH? This happens when the PCM or ECU unit has trouble accessing and determining the actual speed. That resulted in the speedo getting the wrong output and showing an incorrect reading.

The Solution

Use a scan tool and insert it into your computer and car OBD II port (underneath). Then, access and wait for all the fault codes to pop on in the pending list. Reset the fault codes like you usually do by hitting the Start button.

Issue 4: Speedometer at Zero

If your speedo’s indicator needle stays in the 0 and doesn’t move at all, this means the fuse is burnt. Sometimes it can occur if the speedometer needs replacement.

The Solution

  • Locate the fuse compartment in your 97 GMC Sierra by checking the owner’s manual.
  • Then, find the speedometer fuse which is 20.
  • Remove that and insert a new fuse. Test it out.
  • If still the speedo stays at 0 MPH, then the speedometer needs an inspection.
  • Remove the front and side panels (around the speedo) using a pry bar.
  • Take out the dash trim.
  • Take a screwdriver to detach 3 screws (in most cases).
  • Then, carefully unplug the plug to remove the instrumental cluster.
  • Insert a new instrumental cluster and plug the wire into the back. Push a little to properly align it into the place.
  • Insert the 3 screws and tighten them out using the screwdriver.
  • Add the dash trim and press it to sit properly.
  • Place the front and side panels around the speedo using your hand pressure. Be sure not to break them.
  • Calibrate the speedometer using the OBD II to match the reading.

Ending Note

After learning about the 1997 GMC Sierra speedometer problems, you should try the given techniques to fix those as it doesn’t cost much to attempt.

Solving the issue from Autoshop or via an expert will potentially need around $900 to $1,000 or more based on the causes.

So, I hope this guide leads you to the right solution to fix the real issue. Best of Luck!

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William Baldwin

This Is William Baldwin, The Founder & Managing Editor of this website. Me and my team share automotive tips, tricks, and news