There are two different styles of glass run channel. A single piece design, and a two piece design. Which style you have will depend on the year, make, and model of your vehicle. The single piece design consists of one complete channel that goes up the back of the door glass, across the top and down the front side of the door glass. The two piece design consists of an upper channel that goes up the back side of the door glass and across the top, and a division post run that will apply vertically to the door glass side of the vent window post. You may use similar installation techniques for either design.
Start by removing you door panel and removing the old weatherstrip. To begin installing the new weatherstrip it will be helpful to lubricate the part with soap and water or Precision’s Weatherstrip Lubricant prior to installation. If your vehicle has a vent window you will not need to remove the bent assembly from the door but it will need to be disconnected. Once the part is lubricated and the vent assembly is disconnected, line up the corners of the new weatherstrip with the corners in the door glass opening.