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| AC Compressor Switches (Page 2/7) |
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mike-ohio
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MAR 07, 11:46 AM
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Lou6t4gto
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MAR 08, 07:53 PM
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funny, I installed a new comp in my 85 five years ago WITH NO SWITCHES, and it blows ice cold.( I Live in FLA.) I believe that the 1 pressure switch at the drier up front will shut it down if it runs out of freon. So aren't those switches at the compressor "Redundant" ? "Good Post Info"
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RWDPLZ
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MAR 08, 08:02 PM
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Technically it will work with no switches in a DA6 or HR6 system, BUT the switches are safety devices. The fan switch one is redundant, but the high pressure cut-off switch is definitely a good idea to have.
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randye
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MAR 08, 08:31 PM
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| quote | Originally posted by Lou6t4gto:
funny, I installed a new comp in my 85 five years ago WITH NO SWITCHES, and it blows ice cold.( I Live in FLA.) I believe that the 1 pressure switch at the drier up front will shut it down if it runs out of freon. So aren't those switches at the compressor "Redundant" ? "Good Post Info" |
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From what I know of the 87-88 model years, (your 85 might be different), the switch up front at the receiver / dryer is a pressure CYCLING switch.
It turns the compressor on and off to maintain a selected system operating pressure.
That switch is adjustable, (such as when we set it for using R12 or R134A in the system which operate at different optimal pressures)
The radiator fan is also turned ON by the HVAC control head inside the dash when "A/C" is selected.
The two switches on the DA6 and HR6 compressor are arguably "redundant" (non-adjustable) safety switches, but considering the repair expense to the system from a failure of either of the two aforementioned switches, I am happy to know they are there and working properly.[This message has been edited by randye (edited 03-08-2013).]
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masospaghetti
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MAR 26, 12:32 PM
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| quote | Originally posted by randye:
From what I know of the 87-88 model years, (your 85 might be different), the switch up front at the receiver / dryer is a pressure CYCLING switch.
It turns the compressor on and off to maintain a selected system operating pressure.
That switch is adjustable, (such as when we set it for using R12 or R134A in the system which operate at different optimal pressures)
The radiator fan is also turned ON by the HVAC control head inside the dash when "A/C" is selected.
The two switches on the DA6 and HR6 compressor are arguably "redundant" (non-adjustable) safety switches, but considering the repair expense to the system from a failure of either of the two aforementioned switches, I am happy to know they are there and working properly.
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The fan control switch on the compressor is not really redundant. In defog mode, the control head does NOT command cooling fan operation (try it and see), but it does turn on the A/C compressor. The fan control switch turns on the fan once pressure in the a/c system rises.
Without it, your dehumidify function for the defogger won't work as well.
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sricka01
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APR 29, 12:49 AM
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How do you know the orientation of where to install the hi/lo pressure switch? Not sure which switch goes into the respective ports.
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Marvin McInnis
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APR 29, 11:24 AM
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| quote | Originally posted by sricka01:
Not sure which switch goes into the respective ports.
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Either switch can be installed in either port. Both ports communicate with the compressor's high-pressure manifold. That said, the wiring harness may favor one switch placement over another.
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sricka01
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APR 29, 09:12 PM
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| quote | Originally posted by Marvin McInnis:
Either switch can be installed in either port. Both ports communicate with the compressor's high-pressure manifold. That said, the wiring harness may favor one switch placement over another. |
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Wow, thank you Marvin. Of all the threads nobody mentioned this. I was stressing over looking at pics trying to figure out if there were stampings to explain which was LO or HI side.
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FieroGT42
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JUN 11, 09:43 PM
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Here is a link to Santech's illustrated catalog and application guide. Everything you needed to know and then some. Page 79 (81) has identification, switch pressure specs, alternate part numbers and more.
After a shop sent me the wrong switches twice, and then the wrong pigtails, I used this catalog to get exactly what I needed. Hope it helps some others.
Jason
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Boxdin
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JUN 27, 07:20 PM
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I would say its mandatory to replace the two switches. My 88 4cyl went 263,000 miles on the orig AC then one day I heard a swish type sound and no AC.
Upon autopsy the high side switch had broken and pressure got high enough to pop the safety valve. As seen above I was able to get 2 new switches of the right color and put them in w my new system.
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