Abs problems

[Blackfoot]

Recently replaced front bearing assemblies on my 06 Sierra 2500hd. Came with new abs sensors installed. Now the abs on the passenger side sets off around 5mph and pulls the truck to the right. Stops fine when you disconnect the connector by the frame. All the wiring looks good. Any ideas what the problem might be? 

[Formulabruce]

Dirt, or small piece of rust below the sensor. air gun may do the trick