Where is the crank sensor located in a 97 lesabre custom?

Facing the front of the engine, you will see it on the right side of the crank shaft. Mounted behind the balancer. You would have to remove the balancer to replace it.

To find the CRANKshaft sensor,
try looking from the passenger side of the car.
The CRANKshaft sensor is behind the passenger front wheel side of the engine under the engine harmonic balancer wheel at about the 3 'o'clock position.

The passenger wheel is removed and then the wheel well splash panels where the balancer wheel is visible and then removed to replace the sensor.