nmaschek

I'm looking at getting a 2003 GS300, but the A/C compressor intermittently turns on and off. It does this for a few minutes when you start the car and then eventually it will fun as normal.
Here's is a video of the compressor...


And here is a video of the RPM when this is happening...


Thoughts on what could be wrong?
Thanks.

Mr Jokster

iTrader: (8)

First thing to check is your pressure, could be low on freon.

nmaschek

I'll take a look at that thanks.

It does this for about a minute after startup and then the compressor runs fine with cold A/C.

Clutch electromagnetics?

Mr Jokster

iTrader: (8)

In that case, it too could be the pressure switch located here:

nmaschek

That seems reasonable after looking it up.

How would one know if the compressor needs to be replace all together? (Along with the dryer of course)

Mcon

iTrader: (1)

Mr Jokster,

You always helping around here in this forum. Where is the like button LOL

Yesterday, my A/C system started blowing hot air through the center vent and the A/C button began to flicker, I turn the A/C off.

Today, my first step was to check or do the screen test, just in case the screen show me something and just showed 00. So, that is check and is okay.

Next step, I put the exhaust gauges and the gauges show that the system have Freon, but I discovered that the compressor does not start.

Next step, I check if the A/C relay work or not. I swap one of the relay fan # 3 with the A/C relay, because are the same and have the same part number and nothing. Relay check

Next step, I disconnect the wires plug from the compressor to see if one of the cable bring power to the compressor, but the only thing that I found out was that all 3 wires have ground only, no power. Only one of the 3 cables when I check, the ground was very low in my tester tool and flicking a little be. So, no power at all on the 3 cables.

Maybe is the pressure switch as Mr Jokster say that need to check. But I do that or check that switch in a few day. Enjoy your day guys

Mr Jokster

iTrader: (8)

I'm leaning more towards the pressure switch. Your clutch seems to be working just fine, even though its engaging and disengaging over and over. Being that it is shows that the clutch is fine. A faulty compressor usually is from a busted clutch where it seizes engaged or disengaged (which we've ruled out) and bad bearings on the compressor itself. If the bearings were bad, you'd hear nasty noises coming from the compressor that are easily distinguished. I believe one of the 2 suggestions I gave are gonna be the culprit.

Mr Jokster

iTrader: (8)

Hey, I think you may have more of an electrical problem at the switch than anything else. Remove the button panel and see if the wires look ok. If you can reproduce the 'flicker' while the panel is out of the dash, move the wires and see if you can stop it from flickering.

If you have a local friend with a GS, you may try swapping the panels and see if the problem persists.

Also, you said it was blowing hot air through the center vent, was that ONLY through the center vent and cold through the outside vents, or hot all the way around? Could be a servo issue too.

nmaschek

Awesome! I haven't bought the car yet, but I'll tell the dealership to change out the pressure switch and I'll buy it! Thank god the A/C actually works because it's like 95 in Fort Worth now everyday, good time to check if the A/C truly works 😄

Mr Jokster

iTrader: (8)

well shoot, if the dealer has it, then they should be able to figure out what it is and fix it Hope they check the switch before replacing it because its pretty pricey to change and it not be the problem. I assume that they checked the freon already?

nmaschek

Well it's not a big dealer at all. Just one of those little corner lots with one guy running the office. But still, I'm telling them I want the car with working A/C then I'll get it.
I'll have them check the freon...a low freon level could trigger the compressor to turn on and off like that?

Mcon

iTrader: (1)

Mr Jokster
Also, you said it was blowing hot air through the center vent, was that ONLY through the center vent and cold through the outside vents, or hot all the way around? Could be a servo issue too.

My Bad. Is through hot air for all vent, not only for the center ones. So, I don't think they are the servo motors.
But is a guy like a 30 min. from me that part out a GS. I want to see if he let me test his button panel But Mr Jokster, remember I test my button panel and show that everything was good. Screen show 00.

Thanks again for you input. I let you know what I found out.

Mr Jokster

iTrader: (8)

Yes, that's why it could be that or the switch. The switch is a safety switch to protect the compressor. The compressor can overheat if its too low on Freon. If the Freon is at the 'in between' pressure, the switch keeps detecting that there's adequate pressure, then all of a sudden OOPS, not enough, then oh wait... yea there is... awe man, no there's not etc. Get it? The switch will disengage the clutch to prevent the compressor from any damage. Think of how an old mercury thermostat in a home works. When it gets hot the spring tips the merc to one side and completes the circuit then when it cools down, the merc falls the other direction and disconnecting the circuit. Figuratively, if the spring gets loose and doesn't hold it firm, the merc will splash back and forth toggling the switch off and on because its not stable and that's what happens with the low Freon level, its not at a stable psi and could be doing what I mentioned.

As I also said, if its the switch (assuming its a spring loaded switch like most, there are different types) the spring may have seized with just enough spring load to bounce the switch off and on.

Mr Jokster

iTrader: (8)

Yea, but that just shows that the computer is working. You mentioned that the light is flickering on and off which could be a bad connection. So in a sense its like if you were to press the button off and on real fast with your finger, but being that there may be a loose connection, the wires arent making good contact creating a short when you attempt to turn it on. Try holding the button while turning it on and see if it keeps it cold.


Is it getting cold at all anymore, do you hear the compressor clutch engage and disengage when you press the button?

nmaschek

Thanks Mr. Jokster for that detailed explanation of the thermostat. It helps me understand how it all works! It makes sense now. Glad I came here first.