Broken A/C switch '78 924
06-21-2001 | 09:45 AM
#1
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5th Gear
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From: Florida
Broken A/C switch '78 924
I've found a '78 924 in a salvage yard and
hope to get the A/C switch I need for my
car.....does anyone here have experience
removing the switch? how do I disconnect the
small capilary (copper) tube that goes from
the switch to the evaporator coil?
TIA,
don
hope to get the A/C switch I need for my
car.....does anyone here have experience
removing the switch? how do I disconnect the
small capilary (copper) tube that goes from
the switch to the evaporator coil?
TIA,
don
06-21-2001 | 02:20 PM
#2
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From: Royal Oak, MI
Hmmm... this sounds like it might be one of the DPD aftermarket (dealer-installed) AC units. Where are the controls located? The factory AC units had the controls above the radio, above the heater controls, in one integrated round switch. The DPD (David Paul Designs, I think) switches had a console/housing added below the radio, with two separate round switches, and a round "DPD" emblem in the middle.
Furthermore, as I recall, the factory AC control did not have a tube to the control switches, only wiring.
Answering this question should help generate the correct answer to your question...
Furthermore, as I recall, the factory AC control did not have a tube to the control switches, only wiring.
Answering this question should help generate the correct answer to your question...
06-21-2001 | 03:44 PM
#3
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5th Gear
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From: Florida
Vaughn,
This IS the factory installed unit,
it has a large round **** above the heater
slide controls, and sits between the oil pressure guage and the clock, (in my car at
least) there are four vacumn lines going to
the switch and at least six wires in addition
to the "capillary" tube thingy.....
the part # is:477959511
temperature is controlled by rotating the
****, and fan speed is controlled by pulling
the **** out to one of three positions.
Hope this helps identify it better.
-don
This IS the factory installed unit,
it has a large round **** above the heater
slide controls, and sits between the oil pressure guage and the clock, (in my car at
least) there are four vacumn lines going to
the switch and at least six wires in addition
to the "capillary" tube thingy.....
the part # is:477959511
temperature is controlled by rotating the
****, and fan speed is controlled by pulling
the **** out to one of three positions.
Hope this helps identify it better.
-don
06-21-2001 | 10:02 PM
#6
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5th Gear
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From: Florida
whats the tube thingy do anyway???
anyone?? must be the thermostat? if it
just transfers temperature along the skin of
the tube, i should be able to just
solder it back together, but if it
has to carry air/vacumn/freon through the
tube it'll be next to impossible.
anyone?? must be the thermostat? if it
just transfers temperature along the skin of
the tube, i should be able to just
solder it back together, but if it
has to carry air/vacumn/freon through the
tube it'll be next to impossible.
06-23-2001 | 06:56 AM
#7
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From: New Zealand
There are two types, one is the mercury capillary thermostat, there is a capsule at the end of the tube that holds the mercury, when temp increases the mercury expands and moves the diaphragm behind the ****, this switches the contacts at the set temp.
This capillary tube is filled with mercury and once broken is trash. The tube and the A/C evaporator are one piece as the capsule is embedded in the evaporator.
When mine broke I replaced it with a standard refridgeration thermostat and simply cable tied the capillary tube hard against the evaporator (as any A/C shop would repair in this way).
There are no vacuum tubes on this switch, there is a vacuum relay that operates when the A/C is turned on to control the flaps.
I moved mine to where the lighter was and wired the fan speed through the heater switch with a relay to change over the fan control when the A/C is on.
The other type is an electronic amplifier with a potentiometer and a thermistor to set the temp. They both look the same from the front.
Pics are on my website, I replaced the A/C control **** wiht a clock.
This capillary tube is filled with mercury and once broken is trash. The tube and the A/C evaporator are one piece as the capsule is embedded in the evaporator.
When mine broke I replaced it with a standard refridgeration thermostat and simply cable tied the capillary tube hard against the evaporator (as any A/C shop would repair in this way).
There are no vacuum tubes on this switch, there is a vacuum relay that operates when the A/C is turned on to control the flaps.
I moved mine to where the lighter was and wired the fan speed through the heater switch with a relay to change over the fan control when the A/C is on.
The other type is an electronic amplifier with a potentiometer and a thermistor to set the temp. They both look the same from the front.
Pics are on my website, I replaced the A/C control **** wiht a clock.
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06-23-2001 | 08:58 AM
#8
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5th Gear
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From: Florida
Hello Martin,
It seems you know quite a bit about this
type of switch.Thank You for the ideas.
I don't like the idea of trying to remove
the evaporator from the salvage unit and
will probably try the "standard refrigeration" unit you spoke of.
Thanks again,
don
It seems you know quite a bit about this
type of switch.Thank You for the ideas.
I don't like the idea of trying to remove
the evaporator from the salvage unit and
will probably try the "standard refrigeration" unit you spoke of.
Thanks again,
don
07-11-2001 | 12:33 PM
#9
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Joined: Jul 2001
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From: Glendale Heights, Il
The '77-'78 924 factory A/C is different from the '79 and later system. The Late system was manufactured by Nipondenso for Porsche. The early system was put together by Porsche. The early system used a Sanko (now known as Sanden) compressor and was adapted to use the regular heater blower. The control was a complicated one mounted in the center gauge hole in the console and had a temperature thermostat as part of the assembly. The later system had this part in the evaporator assembly. The t-stat has a capillary tube that extends from the switch to the evaporator. This tube is filled with refrigerant that expands and contracts to control a small microswitch that turns the compressor on and off. I have a complete early system from a car that I parted out. I had replaced this thermostat with one made by Ranco. (this came from an Ice Maker) When this switch was available from Porsche it was VERY expensive so when mine stopped working I found a t-stat that worked. It can be done. My advice would be to find a t-stat for a window air conditioner as this will have the correct temperature setting.
07-11-2001 | 10:07 PM
#10
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From: Florida
Originally posted by pst:
<STRONG>The '77-'78 924 factory A/C is different from the '79 and later system. The Late system was manufactured by Nipondenso for Porsche. The early system was put together by Porsche. The early system used a Sanko (now known as Sanden) compressor and was adapted to use the regular heater blower. The control was a complicated one mounted in the center gauge hole in the console and had a temperature thermostat as part of the assembly. The later system had this part in the evaporator assembly. The t-stat has a capillary tube that extends from the switch to the evaporator. This tube is filled with refrigerant that expands and contracts to control a small microswitch that turns the compressor on and off. I have a complete early system from a car that I parted out. I had replaced this thermostat with one made by Ranco. (this came from an Ice Maker) When this switch was available from Porsche it was VERY expensive so when mine stopped working I found a t-stat that worked. It can be done. My advice would be to find a t-stat for a window air conditioner as this will have the correct temperature setting.</STRONG>
<STRONG>The '77-'78 924 factory A/C is different from the '79 and later system. The Late system was manufactured by Nipondenso for Porsche. The early system was put together by Porsche. The early system used a Sanko (now known as Sanden) compressor and was adapted to use the regular heater blower. The control was a complicated one mounted in the center gauge hole in the console and had a temperature thermostat as part of the assembly. The later system had this part in the evaporator assembly. The t-stat has a capillary tube that extends from the switch to the evaporator. This tube is filled with refrigerant that expands and contracts to control a small microswitch that turns the compressor on and off. I have a complete early system from a car that I parted out. I had replaced this thermostat with one made by Ranco. (this came from an Ice Maker) When this switch was available from Porsche it was VERY expensive so when mine stopped working I found a t-stat that worked. It can be done. My advice would be to find a t-stat for a window air conditioner as this will have the correct temperature setting.</STRONG>
i've pretty much figured most of the wiring out, and will probably do as you and Martin
suggest, RE: the t-stat.......i've had the system converted to R134 with a new dryer, system cools now, i have the t-stat bypassed and i am using my unused foglight switch to turn the compressor off/on until i get a suitable t-stat.the ducts need some work and i need to replace the mostly missing vacumn lines to the air flaps.
thanks again for the help,
-don
