I cannot switch my environmental selector, I can alternate between cool and heat ok; but when I try to position the air to the dash vents or floor it only blows through the defrost. I suspect that the culprit is the switch itself, has anyone else had the same problem? Thanks for your help y'all.

 

What year Ranger?


No not the switch, the vents are operated by Vacuum, Defrost is the Default position of the vent doors, so with no vacuum you get Defrost
Most common cause of no vacuum in the cab is the Black vacuum hose that connects to the Vacuum reservoir in the engine bay
Black vacuum line will come out on passenger side firewall, next to blower motor housing, may also be a grey vacuum line next to it(it runs to heater hose valve)
The black vacuum line can be hard plastic so "looks like" a wire, follow it, it often breaks or melts near exhaust system, it can be repaired with tight fitting rubber vacuum hose

It will run to Vacuum reservoir, its location can vary by YEAR of Ranger, vacuum reservoir can look like a black plastic BALL, it stores vacuum(like power brake booster does)
If it was leaking then you would have Vent control while idling, but when accelerating vents would change to Defrost, because vacuum is lost on acceleration, but comes back at idle, the Reservoir holds vacuum so that doesn't happen

On my 1994 Ranger vacuum reservoir is small and sits on top of blower housing
In later years it can be lower down on passenger side at the front by rad support, have to get under front bumper to see it

 

1999

 

So it connects the heater control valve and snakes into the cab. Based on my '99, is it a very thin grey hose by chance? If so, it has been giving me the fits, very brittle. A pain in the Obama.

 

There are TWO vacuum hoses, the grey one comes from the cab and goes to the heater hose valve

The Black one is the Vacuum source, grey one can't work unless black one is OK, neither will the vents

Find the Black one

Heat control in the cab, COLD-HOT ****, controls an electric motor on the Blend Door in the cab

Google: Ranger Blend Door

These were a problem

Blend door routes air from the fan thru the heater core or around the heater core, so sets air temp

The Grey vacuum line is usually only used in MAX AC setting, cuts coolant flow thru heater core, its not used for adjustments to heat levels

 

Thank you, Ron D. Your information was very helpful.