I was going to empty & refill my A/C coolant, so I bought the Harbor Freight A/C Manifold Gauge set. My A/C for about the past 3 years works most of the time, but sometimes does not. While using the gauge today, I realized my fan was not on once the A/C turned on. Is this a relay issue? When the A/C is on, but the fan is not running: Low side=90psi High side=90psi. When the fan kicks on: Low=110 & High=150-165. Are these numbers correct for my car? I only see I need 410g of R-134a, but I don’t know if that translates to that. Thanks to @George_San_Jose1 @Nevada_545 @davesmopar @old_mopar_guy @asemaster for your help with my last issue. The OBDII is still in the green.
Why were you going to do that?
Tester
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+1
With all due respect A/C is not really a DIYer type of thing you need to mess with, it requires knowledge of how the AC system works including (reading) the pressures, having the proper tools and knowing how to use those tools… And if you are having to ask if those pressures are good or not then it is obvious you do not have a working knowledge of a HVAC system… And doing the wrong thing can cost you hundreds even thousands of dollars in repairs, if you have to take it to a shop… And there is not much worse then going behind a DIYer and try to figure out what all they screwed up… It’s not like changing a wheel bearing or doing your own brakes or suspension repairs or even chasing down a misfire…
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No difference in pressure: the compressor is off, fan not needed.
Low side pressure too high, did the compressor operate for at least 30 seconds?
Yes, I had it on for about 5 minutes after the fan kicked in.
Thanks. My main question is about the fan not operating. It should be on at all times when the A/C is on, right? I noticed the A/C blows warm when the fan is off & cold when it’s on. I’m thinking a relay might be blown. But, I agree with you that I shouldn’t mess with the coolant, but a relay or fuse or something electronic I can replace. I just don’t want to mess with the wrong thing.
Yes the fans have to be on when the AC compressor is engaged for it to work properly… (edit: on the older cars from what I remember anyway)
And can you see the ac compressor clutch spinning when the AC is on and the fans are off?? not the pulley but the clutch…
Tester normally can post the wiring diagrams for you…
FYI, Freon goes in the AC system, coolant goes in the engine cooling system/radiator…
And I also don’t think you have the manifold gauges hooked up properly or the gauges are defective one… lol
Dave- many cars of today do not bring the fans on whenever the compressor is engaged. They only start the fan when the high side pressure requires it. I dont know if a 2006 Saturn uses that strategy.
I can check the configuration tomorrow, generally when an A/C pressure sensor is used, the fans are switched on when the pressure reaches 175-225 psi. If you find that the pressure is high and the fan is off, wiggle the wiring connector at the pressure sensor, see if the fan switches on.
Yeah I figured as much after I posted it, and I almost changed the wording but not sure if it mattered on the 2006 Saturn’s… But with it being Hot outside, the head pressure should be high enough to kick the fans on regardless… Since the head pressure should be ambient temperature X2 plus 50, hitting 175-225 psi should be easy to get to and with no air flow across the condenser the head pressure will normally climb pretty fast and with no fans should go very high cutting power from the compressor to keep from damaging it…
I was helping a friend with his 1st big AC job and he had removed the fan assembly for the condenser replacement and decided to start the vehicle and check to make sure everything worked ok before finishing installing everything and I just watched him trying to figure out why the high side kept going so high, he kept evacing the freon and recharging the system thinking he had to much in it and after doing it a few times I asked him how the air flow was across the rad/cond and then he gave me a dirty look and remembered the fan was not installed… Yes I was trying to make him think about how the system worked… I got a kick out of it and he learned something… lol… The AC worked great once the fans were hooked up and running… No he didn’t leave it running long enough to overheat the engine, but the fan was a pita to R&R…
I meant freon, of course. The gauges are brand new & they must be hooked up correctly, since the high & the low are different sizes. Tomorrow I’ll check @Nevada_545 's connector.
@Nevada_545 @davesmopar @old_mopar_guy
Update. Today I drove for a while before checking the gauges. The A/C worked perfectly.
A/C on: Low=26 psi, High=140 psi
A/C off: Low=70 psi, High=95 psi
I watched some YouTube videos & the A/C on seems perfect, but off should be closer to the same psi.
@Nevada_545 Wiggling those wires, I guess, won’t help since I’m nowhere near 175-225psi. I’m going out there now to see if maybe the A/C wiring at the switch is loose, causing it to sometimes not work.
If your air coming out of the vents is col, just leave well enough alone. 26 on the suction side should be getting you plenty of cold air.
If the pressure is below 175 psi, the cooling fan must be on.
I’ll go out & check tomorrow. It stayed on every time I checked it today. Thanks. I’ll raise the car to find the wiring you mentioned yesterday. It must be under the car, since I can’t see anything from above.
What is the ambient temperature when you are reading the gauges at L29psi and H140psi??
Plus have you measured the dash vent temp??
I’m in the south with normal high humidity, so in my neck of the woods, that is low for 80+ degree temps…
But like o_m_guy said, if it feels good then leave it alone… lol
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It’s still Spring here in Los Angeles. 72F 57% humidity when I did it yesterday according to the NWS. The only issue is why does it sometimes does NOT work. Once I drove to Vegas & stopped at a rest stop & the A/C did not work for about 30 minutes while driving in 100+F, but it kicked in after stopping at the next rest stop.That’s my only issue. I thought maybe the freon needed replacing, but I see it doesn’t.
Even if the A/C button is pressed on, the powertrain computer probably won’t allow the A/C compressor to run if the coolant temperature reaches above a certain limit. The computer’s thinking is that a slightly overheated passenger is preferable to a heat-damaged engine.
Thanks. Maybe it won’t do that now that I fixed the OBDII code that you’ll remember everyone thought I needed a new thermostat, which, as we learned, I did not. I guess all issues are related. The final issue I have with the car is Levels 1&2 don’t work on the A/C, but 3&4 do. I checked yesterday & the psi did not change much when going to 1&2, but the fan was completely off. Is this a wire that broke, or a fuse? Again, I don’t want to start messing with things when I might get a direct answer here. 1&2 haven’t worked at all, not even once, in a few years.
Sorry, I forget what that issue turned out to be.
I presume those are the engine compartment blower fan speeds, 2 lowest speeds. Do 1 & 2 not work in the winter too, heat mode? If so, pretty common problem by reports here for many cars, usually it is just the lowest speed that doesn’t work. Speed 1 hasn’t worked on my Corolla for ages. The reason it fails that way, the electrical power is divided between the fan motor and something else (on my Corolla, a gadget called a blower resistor). High fan speeds, most of the power goes to the motor, very little to the gadget. Low fan speeds, only a little of the power goes to the motor, most of the power goes to the gadget, which promptly gets hot and fails. Me, I just live with that problem, not worth the time spent to fix it.