Entire AC system replaced 3 years ago - poor cooling high low side PSI?

Hey gents

a few years ago my compressor went so I went through the process of replacing everything including a leaky line as well as flushing the evap core. I’ve also replaced the clutch relay and replaced the sensor on the compressor. The only part I did not replace besides the evap core was the ac amplifier behind the glove box. As of late I noticed the blinking light more blowing hot air. While its not blinking, I have the uneven cold air displacement issue through the vents where the most drivers side vent is coldest with the temps warming up as you hop to each vent towards the passenger side. I went to measure the pressures last night (around 65 degrees ambient temps) with the truck off low side was around 10 psi and the high side was around 97 psi. With the truck on I noticed my high reading just under 100psi and my low side staying around 90psi. Should I have it discharged before trying to add any refrigerant? I’m
Hoping I didn’t accidently suck air into the system yikes. :/

 

So when the engine is running,is the compressor engaged?

 

The flashing AC light means the compressor rpm is not spinning at the same relative rate as the engine rpm.
The pressures being about equal tells me, the compressor isn't doing it's job.
(But we don't know why) - Don't jump to conclusion. I'm not saying it is the compressor.

@Dm93 is the resident AC guru here.
He lives in Texas, and replace AC systems about daily in the summer.

He'll be along shortly to help, I'm sure.

 

With the compressor running, high side pressure should be at least around or over 200. Sounds like its undercharged

The flashing a/c light is a separate issue. Like mentioned above it flashes when compressor speed doesn't match engine speed

 

I don't know about guru, I'm not an A/C expert by any means but I know enough to diagnose and fix most of them.


Sounds like you potentially have two issues:

Low pressures and weak cooling: Either low on refrigerant or there's a restriction in the condenser.

A/C Light flashing: An issue with the compressor Lock Sensor/circuit, compressor clutch, or belt slipping

 

You know what? I changed the belt twice in a matter of a few months. I’ll inspect the belt and the pulleys and of course the tensioner. The AC light flashing has occurred for years even after replacing everything (everything except for the ac amplifier). I’m going to swap the amplifier. I found one for a little over 100$ yet on the same site the same part for around 400$ ???

the condenser is even newer than the compressor as I hit a deer in early 2023 and my condenser was shooting Freon everywhere.


I also noticed the can of refrigerant when i tapped it I had actually opened it then closed it hence why no refrigerant was coming out into the system. I’ll try to add it again. I got worried seeing the low side pressure jump to 90psi and stay there. I’ll add uv dye as well. Thanks for your responses guys.

 

Hey guys I forgot to mention, if the trucks idleing the clutch turns off with the blinking light more. If I open the hood and let the truck idle the ac stays on longer without kicking off with the flashing ac light. What’s that all about?

 

With the engine off, can you spin the hub of the compressor. You should feel mild resistance but you shouldn't have to muscle up for it.

Spin it atleast 10 or more times before making that judgement. A seizing compressor can either be seizing in one spot or after a few revolutions

 

I highly doubt that's your issue, I'd more suspect the Lock Sensor or wiring. The lock sensors in aftermarket compressors aren't known to be particularly reliable.

Could be the belt is slipping, shitty lock sensor, or something else, hard to say without seeing the truck and testing the lock sensor signal.

 

You’ve talking about what Toyota calls the pickup sensor? The sensor is oem I bought it new but the compressor itself is a reman from Napa.

 

Do you cats have documentation on testing the lock sensor circuit? I think I seen it on another post somewhere. The circuit that terminates behind the glove box?

 

You need a lab scope to watch the signal on a screen and compare it to a known good waveform