Where is proportioning valve on 1988 ford e-150?

On a 1988 Ford E-150, the proportioning valve is typically located on the frame rail, near the rear axle. However, the exact location can vary slightly depending on the specific model and options. It's usually a relatively small cylindrical unit with several brake lines connected to it.

To be certain, I recommend:

* Consulting your owner's manual: This is the best resource for your specific vehicle.

* Looking at a repair manual specific to your year and model: A Haynes or Chilton manual will have diagrams showing the location of components.

* Searching online for diagrams: A Google image search for "1988 Ford E-150 proportioning valve location" might reveal pictures of its location on similar vehicles.

Since you're working with brakes, be very careful. If you're unsure about locating or working on this part, it's best to take your vehicle to a qualified mechanic. Improper brake work can be extremely dangerous.