Aircon
its a PITA
if you have the push button airtemp control
1) it will be broken
2) never buy a second hand one it will be broken
3) never buy a second hand one it WILL be broken
4) without it working you will have heater on all the time with the air coming out of the bottom of the heater box at the tunnel
the air temp controls come in a number of styles
All have a vacuum pipe, rubber mainfold pressed onto the back and held with a clip that clamps the rubber pipe connector and the rear of the unit
you need the correct number of buttons and the correct shape connector for the vacuum pipes
these connectors are either D shaped or rectangular i.e D shaped has more pipes across the top than the bottom and the rectangual one doesn't
get the right one
you already have a problem because that in line tap makes me think the vaccum tap on the innder wing on your car is missing or siezed up
find the red and white pipes for it and block them off with a screw each
new chrysler taps of certan vintages are unobtanium or are , oz for oz, more expensive than gold
you can fit one off a small chinese truck, or one off an autralian ford falcon, both the same chinese part, neither is cheap
if the rest of the pipes are there, good... you will have a red and white pair of pipes for each vacuum actuator and 1 black pipe
the black pipe goes to a narrow bore brass pipe brased into a drilled through servo brake bung in the inlet (if you don't have a servo) or to a none ported vacuum take off at the carb if you do.
if all are connected and the air temp control isn't broken...ahahah yeah right, (with the inner wing water control tap siezed someone will have been mashing away at the buttons)....!....... then
start car
free rev it and as you press the control buttons for any aicon feature, gently in. allow the throttle to snap closed to give it a good jolt of vacuum,
if creaking and groaning occurs, the vacuum circuits are working and the air flow configuartion of you combined heater and aircon under dash system should over a period of a few minutes change. it may even switch the switch that triggers the aircon pump pulley clutch provided the thermostat in the aircon box is still wired up.
Two have 2 sets of electricals
1 power for the aircin pump clutch via the thermostatic switch
and a couple of wires to a resistor pack mounted in the box to facilitate 2or 3 speeds on the fan motor.
if sucking noises and lumpy running occurs you have a vaccum leak or a disconnected pipe
do not press the airtemp control buttons hard. you will crack the glue in the back of the unit and it will be broken... by all means put it on the second hand market, at this point, to continue the tradition
if you can't be arsed with any of this and you want heat on the screen
1) open your tap
2) check the cardboard/tinfoil pipes from the heater box go up to the vents in the dash (US and UK motor homes use this stuff for forced air heating so you can still buy it in meter lengths in the correct bore or Try VW beetle heater pipe german and swedeish usually have some)
3) get down on the floor of the passneger side of the car and find the steel rod that runs across the botton of the unit to the vaccum actuator
4) it will be in the "pump hot air out of the bottom position" (i.e warming you gear stick), pull it out from the unit as far as it will go and clamp it with a fat cable tie. add a blob of bostic or sealer
heat will flow to screen all the time
come summer pick off the glue cut off the cable tie and open the windows and the crotch cooler vents, don't wear shorts, you don't want a bumble bee or wasp up the leg, only the centre consol will get hot....
Dave