Lovely, just what I wanted

"DucST3-Red-1Liter-Standing-By" (ducst3-red-1liter-standing-by)
02/26/2018 at 00:24 • Filed to: None

Looks like the a/c compressor on the new Fiesta is shot. Low side refrigerant pressure is off the charts and no sign the compressor is running. Grrrrrr

I could have sworn it was working when we bought it. Maybe it was just because it was cold outside. Anyone know of a decent mechanic in socal? My previous one has lost my business. They messed up a simple coolant reservoir swap. I only had them do it because I didn’t have time to wait for the part and install it myself. This resulted in coolant spilling out for a good couple miles. Glad I checked when I got home

DISCUSSION (16)

traitor joe > DucST3-Red-1Liter-Standing-By
02/26/2018 at 02:02

I would be very cautious about having an unknown shop work on something like my A/C system. That is the type of repair where many mechanics will ring you up for a new compressor even if they know it isn’t needed.

Anyway, if if was working and is now failing to engage, I would suspect a problem with the clutch or relay. Not sure how mechanically inclined you are, but if you’re willing to do some research and can handle a repair like this, you could save a whole lot of money.

Here’s a fun video that might give you some ideas:

merged-5876237249235911857-hrw8uc > DucST3-Red-1Liter-Standing-By
02/26/2018 at 07:40

Yup, what trait... said. It might just be the pressure switch or something simple like that too. If the pressure switch isn’t working properly, it won’t energize the AC compressor clutch. There should be a video about jumping the wires to try and engage the clutch to see if all the mechanical bits work properly first. At least that would tell you if the compressor will work if given the proper signals. And if not, then you can see if the clutch is working or not. But yeah, do some checking before you figuratively drop your drawers at an AC repair shop. At the very least, you’ll make yourself sound knowledgeable if you do end up at the repair shop.

Long-Voyager > DucST3-Red-1Liter-Standing-By
02/26/2018 at 07:46

No warranty?

DucST3-Red-1Liter-Standing-By > traitor joe
02/26/2018 at 08:34

Thanks for the tip. I was actually looking at the relays. Unfortunately, none of the shops have one in stock. Is there some way to test them with a volt meter?

DucST3-Red-1Liter-Standing-By > merged-5876237249235911857-hrw8uc
02/26/2018 at 08:36

Thanks. I did go through the relays and fuses. Fuses look good, but no parts store around had a new relay to try

RacinBob > DucST3-Red-1Liter-Standing-By
02/26/2018 at 08:36

If I assume that “low side pressure off the charts” means there isn’t any pressure, you have already identified that you are out of refrigerant. If that is the case, the low pressure switch will prevent the compressor from starting with no charge and resulting in compressor failure too.

On the lines there are service ports. Pop the cap off and use a screw driver or whatever to depress for an instant the shraeder valve just like on your car tires. If it hisses strongly just like your tire valves should, you have charge. If not, you need someone to determine where the leak is and fix it.

DucST3-Red-1Liter-Standing-By > Long-Voyager
02/26/2018 at 08:37

Afraid not. Only power train left on it for another year or so. Sad face

Long-Voyager > DucST3-Red-1Liter-Standing-By
02/26/2018 at 10:01

Damn, that sucks.

DucST3-Red-1Liter-Standing-By > RacinBob
02/26/2018 at 10:35

Sorry for not being clear, according the gauge I used, the pressure was very high. I will try to push that valve though just to confirm. Thanks!

merged-5876237249235911857-hrw8uc > DucST3-Red-1Liter-Standing-By
02/26/2018 at 14:26

You can swap a similar relay in the ac relay position, if there are any in the fuse box. I was thinking more along the lines of jumpering the ac clutch to, first hear of it engages, and two if the car is running, see if it allows the compressor to spin.

DucST3-Red-1Liter-Standing-By > merged-5876237249235911857-hrw8uc
02/26/2018 at 14:56

Cool, I did some more trouble shooting today. The relay works just fine, hooked it up to another 12 volt battery and the circuit was completed just fine. Power coming to the relay at the fuse box as well

I am starting to suspect the the system might be overcharged. A guy on the fiesta forums had the same problem. I guess when they get overcharged, there is a pressure switch that keeps the compressor from coming on.

RacinBob > DucST3-Red-1Liter-Standing-By
02/26/2018 at 19:49

Huh. High pressure on the evap side while not running? When idle, low and high side should be the same pressure. What kind of pressure are you looking at? I would assume it is in the 70 to 80 psi range...

https://highperformancehvac.com/r-134a-refrigerant-pressure-temperature-chart/

merged-5876237249235911857-hrw8uc > DucST3-Red-1Liter-Standing-By
02/26/2018 at 21:58

Yes likely. I believe they work if they are under charged or over charged, should be two switches, but I’ve never experienced an over charge, only under. But yeah I’d the system is out of whack either way, it had sensors to protect itself. A cheapie harbor frieght gauge set will tell you where the pressures are on the low and high side.

DucST3-Red-1Liter-Standing-By > RacinBob
02/27/2018 at 00:09

It was high, but the cheap gauge I borrowed from a refill can said something above 100 maybe even 150. It didn’t seem to change whether the ac was switched on or off. Taking it in tomorrow to have it drained and refilled. We will get our answer for sure then!

DucST3-Red-1Liter-Standing-By > merged-5876237249235911857-hrw8uc
02/27/2018 at 00:12

According to the cheap gauge I borrowed off a refill can at O’Reillys, it was really high. Taking it in tomorrow to get drained and refilled. So we will have our answer then!

RacinBob > DucST3-Red-1Liter-Standing-By
02/27/2018 at 08:02

The vapor pressure of R-134a refrigerant does not change. So either it was 80 f (100 psi) to 112 f (150 psi) or so, or there is some other refrigerant in it, or the gauge is broken.

The usual suspect is it lost it’s charge, meaning the gauge was broke and something else happened. If not that, then the only explanation if over 100 psi idle in normal temps is someone putting the wrong refrigerant in it.....