Well this is a wierd one and i hope someone can help me. I have a 1992 full-size blazer, 5.7, 33" tires with a lift. Well the light comes on for 3 sec and goes off like it should when you start it. It stays off untill i hit 15 mph and then it stays on untill i go below 15 mph. I don't know what it is. Can anyone help? I have already replaced both front wheel sensors and im not getting any codes. PLease help. thaks in advance.

 

Sounds like it could possibly be a dirty reluctor ring on one of the front wheel speed sensors. This can cut down on the depth of the grooves in the reluctor ring which can cause the ring to appear solid at higher speeds instead of grooved. You may want to try and clean the reluctor ring. I believe it is located at the outer knuckle of the CV shaft on the fullsize trucks.. Just look for the WSS itself and clean what it points at.

 

how would i go about cleaning this?