The loss of vacuum can be caused by a break in a vacuum line or a faulty vacuum switch.
Ford ranger heater control valve vacuum line.
13 vacuum from the engine intake manifold.
A c heater function selector switch.
Water diverter valve full vacuum position 17.
The heater is always on.
15 vacuum to the 4x4 hub solenoids.
A heater control valve can fail in several ways.
I have a ford ranger pickup 1998.
Since a vacuum operated valve defaults to the fully open heat on position when vacuum isn t applied a loss of vacuum is the first thing to suspect in a heat always on condition.
I pulled the dash control out and examined it but don t seem to have a problem visually.
In this video i show you step by step how to replace your heater control valve on a 1997 ford ranger v4 standard 2 3l.
Vacuum control motor air inlet duct door.
I found a broken vacuum line that goes to the coolant hoses and fixed it but it doesn t seem to fix the problem.
10 recirculated air inlet.