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| AC Compressor Switches (Page 3/7) |
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jscott1
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MAY 18, 01:19 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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I know this is an old thread... but I've seen this a few times in the archive... how do you suppose your system is working properly when you disconnected the ground wire?
I would posit that your switch is NOT capable of functioning with the ground disconnected. The so-called "low pressure" switch is really called the "Coolant fan a/c pressure switch". And with the ground disconnected it's incapable of turning on the radiator fan. Is that needed? Maybe, maybe not, but disconnecting the ground doesn't sound like the right answer to me.
My research seemed to reveal that if your fan runs all the time you have the wrong switch.[This message has been edited by jscott1 (edited 05-18-2014).]
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randye
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MAY 18, 07:34 PM
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| quote | Originally posted by jscott1:
I know this is an old thread... but I've seen this a few times in the archive... how do you suppose your system is working properly when you disconnected the ground wire?
I would posit that your switch is NOT capable of functioning with the ground disconnected. The so-called "low pressure" switch is really called the "Coolant fan a/c pressure switch". And with the ground disconnected it's incapable of turning on the radiator fan. Is that needed? Maybe, maybe not, but disconnecting the ground doesn't sound like the right answer to me.
My research seemed to reveal that if your fan runs all the time you have the wrong switch.
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Its been a LONG time since I messed around with the AC on my Fiero, and to be fair I DO indeed recall some sort of issues regarding a ground wire connection and a constantly running radiator fan, but I assure you Ol' Buddy I worked all the bugs out. 
Last I looked, everything was wired up all Kosher and proper.
I believe I even said:
| quote | Originally posted by randye:
The switches are NOT included with the Four Seasons Remanufactured compressor.
You will need to buy the switches AND the new mating plugs for them.
To wire them into the OEM harness is fairly simple. You will just cut the original single switch wires on the car, (do one at a time so that you dont confuse the high pressure cutoff switch with the fan switch), and simply splice in one of the two wires from the new switch plug.
The 2nd wire from each of the new plugs is a ground wire and you should run each of these wires to a good ground on the chassis or engine block.
NOTE: It doesnt matter which of the 2 wires you choose to splice into the harness or run to ground. Both switches simply complete or interrupt a circuit to ground. The reason for the 2 wires on the new switch connectors is that the old single wire switches grounded through the body of the A/C compressor and the new switches do not. Therefore the separate ground wire is required. |
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The fan SHOULD be on constantly when the AC is selected, and the fan should cycle on and off normally with the fan control switch when the AC is off, (on the 2.8 or 3.4 swap), or thru the ECU... depending on your engine swap.
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 [This message has been edited by randye (edited 05-18-2014).]
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Will
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MAY 21, 02:47 PM
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Interesting info... Looking into this for my Northstar, as that compressor only has a high pressure relief valve, but no switches.
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Will
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MAY 21, 02:53 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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Yes, they are redundant.
The pressure cycling switch (on the receiver/dryer in the front compartment) controls the compressor clutch during normal operation.
However, if your pressure cycling switch fails or your fan fuse blows or a few other failures, you'll like having the safety switches in the compressor.
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sricka01
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JUL 24, 05:53 PM
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Bump because this is a good thread to keep out of the archives and also because I am experiencing an issue with these switches.
The problem is the plastic connector tab either broke off or the engine heat severely softens the connections on both my Fieros around the same time.
This means the A/C shuts off in the middle of driving and I have to wait for the car to cool down before I can attempt to plug them back in.
Anyone else have the same problem? I have tried using zip ties to keep them tight but that only helps for so long.
Can I bypass at least the low pressure switch and rewire it directly? I cant remember which one would cause the fan to run constant even if the AC is off.
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tebailey
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JUL 24, 08:14 PM
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| quote | Originally posted by sricka01:
Bump. This question is directed to RWDPLZ and RANDYE. I have an 88 GT that had for lack of a better term an "explosion" from the engine area last fall. A hazy mushroom cloud effect, it was something to see! The compressor was making a bit of noise for several weeks prior to that. I inspected the hoses and they seem fine between the firewall and compressor fitting. The compressor has some seepage around the front clutch area, so I assume the compressor exploded or that one of these switches blew out of the plug.
**If I buy a reman Four Seasons compressor, do they come with these switches installed or do I need to buy these separately?
If they are not part of the package, how do you wire them in to the factory setup? |
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Do not get a reman, spend a little extra and get a new one. The new ones have dowel pins to keep the case aligned and have 10cyls instead of 6. My first reman lasted less than 50 miles, the new one has been blowing cold for a year and draws less on the engine.
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sricka01
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JUL 24, 11:29 PM
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thanks but that's not what I was asking on this latest issue. Two years after the entire repair, the switches have weak clips holding the plug firmly in place. So I will be driving along and they just come unseated or slightly undone from the heat and the AC stops working. Very frustrating. I want to bypass one of the switches and fuse the wires together.
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randye
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JUL 25, 04:50 PM
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| quote | Originally posted by sricka01:
thanks but that's not what I was asking on this latest issue. Two years after the entire repair, the switches have weak clips holding the plug firmly in place. So I will be driving along and they just come unseated or slightly undone from the heat and the AC stops working. Very frustrating. I want to bypass one of the switches and fuse the wires together. |
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Try to put a very small dab of silicone or RTV sealant on one side of the switch on the outside of the plastic housing where it will NOT interfere with the metal to metal contact of the plug. Connect it back up and let it set for a few hours to cure. Make sure both surfaces, (switch and plug), are CLEAN and OIL FREE. Wipe off with alcohol before applying the sealant.
It should only require a tiny spot, approx. the size of a #2 pencil eraser, or less to hold the plug in place and still be able to pull it off later if the need arises.
OH..and yes, *never* buy a *remanufactured A/C compressor like I did. I might last for YEARS and operate perfectly and still be going strong in Florida heat when you overhaul the A/C properly. 
(I don't work for Four Seasons and I sure don't get anything from them for my comments. All I can say is that of the 4 different vehicles that I have properly installed their *remanufactured* products on, NOT ONE has failed for over 4 years of use in Florida summer heat.)[This message has been edited by randye (edited 07-25-2015).]
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tebailey
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JUL 25, 09:07 PM
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You may have had good luck with remans, but if your replacing an HR6 compressor the new design eliminates the weak point in the originals. It's worth the extra $50 for a better designed compressor. It made a world of difference on mine.
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randye
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JUL 25, 09:29 PM
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| quote | Originally posted by tebailey:
You may have had good luck with remans, but if your replacing an HR6 compressor the new design eliminates the weak point in the originals. It's worth the extra $50 for a better designed compressor. It made a world of difference on mine. |
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WHY is everything a pissing contest with you?
What is your problem?
You have no idea about the internal design of the Four Seasons HR6 compressors. If they have incorporated any "improvements" or not.
I offered my advice based on many years of installing both remanufactured AND new components, my experience overhauling Fiero A/C systems and my experience with THIS PARTICULAR BRAND.
Show us YOUR Fiero A/C overhaul thread or even any substantial contribution to this topic over the years here on PFF.
Otherwise, LET IT GO![This message has been edited by randye (edited 07-25-2015).]
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