The Grand Caravan has four wheel speed sensors that monitor the rotation of the tires and their braking patterns. The information that the sensors collect is sent to your Grand Caravan's computer to help it determine road conditions. If even one of the four speed sensors stops working or sends incorrect information, the brake system will suffer as a result. Your van's brakes may lock up continually and fail during wet or snowy braking attempts. You can locate and replace any of the Grand Caravan's wheel speed sensors, if necessary, right at home. With a car jack and a few tools, the task should take 35 minutes to do per sensor.
Open the driver's door of your Grand Caravan and fully engage the emergency brake. Loosen, but do not remove, each of the lug nuts on the passenger's side front tire of the van with a lug wrench.
Raise your Grand Caravan with a car jack just behind the tire. Place a jack stand beneath the van's frame rail near the car jack for extra support.
Remove each of the lug nuts completely with the lug wrench. Pull the tire off the wheel studs and roll it away from your work area.
Locate the wheel speed sensor for the passenger's side front tire. With the tire removed, you should see the brake rotor--a flat, disc-shaped component--and the brake caliper. The brake caliper mounts on the upper side of the brake rotor like a vise and has a small black hose--the brake line--connected to the top of it. On the inner side of the brake rotor across from the caliper, you will see another black hose. Follow this hose to its ending point at the back of the rotor and you will see a small bolt for the wheel speed sensor. Each of your Grand Caravan's other tires has a speed sensor mounted behind them as well.
