The Location of a Vehicle Speed Sensor in a 1997 Chevy Blazer 4.3L

by Jody L. Campbell
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There are two types of vehicle speed sensors (VSS) on the 1997 Chevy Blazer. One is a single variable speed sensor that sends a signal to the digital ratio adapter control and cruise control. The variable speed sensor is responsible for the speedometer reading in the Blazer. The other type of speed sensor on the Blazer is the antilock brake system (ABS) wheel speed sensors. These sensors read the individual wheel speeds to communicate with the ABS system. Four-wheel, disc-brake model Blazers have four sensors. Rear-drum-brake models have only two.

ABS Wheel Speed Sensors

Step 1

Apply the parking brake on the 1997 Chevy Blazer.

Step 2

Start the engine. Turn the steering wheel all the way to the right (to locate the driver's side front sensor). Shut the engine off.

Step 3

Kneel by the driver's front tire and locate the thin black wire that comes down from the front frame rail and disappears behind the front wheel.

Crawl beneath the rear portion of the front left tire with a flashlight or shop light (if necessary). Follow the black wire to the ABS wheel speed sensor. The wire runs directly into the sensor behind the hub that contacts the cogged metal ABS ring. The right front (passenger side) speed sensor is located in the same place behind the passenger's side tire. Rear-wheel disc-brake models of the 1997 Blazer have speed sensors connected to the rear wheels the same way they connect to the front wheels. Rear-drum models do not employ rear-wheel speed sensors on the rear ABS system.

Variable Speed Sensor

Step 1

Apply the parking brake on the Blazer.

Step 2

Crawl under the Blazer directly below the driver's seat for two-wheel drive models or a little further back for four-wheel drive models. Have a flashlight or shop light at your disposal, if necessary.

Step 3

Focus on the upper left (driver's side) tail shaft of the transmission of the two-wheel drive model or on the upper left (driver's side) tail shaft of the transfer case attached to the rear of the transmission on the four-wheel drive model.

Search for the wire harness coming from the front of the Blazer. The harness attaches to the sensor screwed into the transmission tail shaft or transfer case tail shaft. Identify the sensor by the 1-inch hex head at its base that is screwed into the tail shaft.

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