'01 A/C does not kick on at all (including green light)

Hello all! First post here and new owner of a '01 4Runner as of two days ago!

So I bought this car not knowing for certain what the problem was, but according to the seller, they brought it in to a shop and diagnosed it as some sort of switch/button issue after it stopped working on them. They never fixed it because they live on the coast, so never really needed it. I, however will be needing it with summer right around the corner! (Sacramento, California)

I have a manual A/C system.

I tried to do as much research as I could, but I personally was not able to find too much info for this year 4Runner. I tried searching for the A/C magnet clutch relay behind the glove department, but I don't have one, I even sourced a used one from the junkyard.
I believe that might be for older models, or maybe automatic A/C.

I'm thinking it is for certain an electrical, fuse, or relay issue. Solely because when I depress the A/C and recirculate air button, nothing comes of it. (No flashing light as well)

So I'm not quite certain if it indeed is some fuse/relay issue that I cannot find, or if I just need to replace the entire A/C control unit.

Let me know what you guys think please, I am stumped and would appreciate the help.
I will attach a photo of my climate control unit below.



Thank you in advance!

 

The first place I would look, in the engine bay, is a pressure switch that looks for a refrigerant precharge. The purpose of the switch is to protect the compressor in the case of loss of refrigerant. The pressure switch will be on one of the lines coming off of the compressor. Follow those until you find it. It will have a connector that will likely have two wires. Remove the connector, and jumper the contacts, and then start the truck, engage the A/C switch, and then look at the compressor and see if the magnetic clutch has engaged.

 

Sounds good! I will definitely give this a shot first thing in the morning.
Thanks for step-by-step

 

This will tell you if there is enough refrigerant in the system. The other thing you could do when it is disconnected at the pressure switch (assuming the pressure switch is working) is put your ohm meter on the two pins on the switch side - if it shows continuity, then there is likely enough refrigerant in the system.

 

I ended up testing it just now haha, but I believe I jumped the pressure switch near the low side fitting with no changes.


Clutch also not engaging

I attached a photo of the switch I jumped and a video of myself trying to activate a/c after doing so.
https://youtube.com/shorts/oeZy4bCs17s?feature=share

 

I wonder if the 2001 has a fuse under hood for A/C like my 96 does. When I was trying to replace the A/C button because the face fell off, I tried two new buttons thinking they were both faulty. Discovered a blown fuse under the hood and after that I was good to go.

 

Do you recall the lights not illuminating and which fuse it was, or amp? I did pull all the smaller fuses to just check and they were all good. Also pulled a 50a heater fuse from the same 1997, just as a spare, so maybe later I’ll try that fuse instead.
I read somewhere that the 50a heater fuse also deals with other a/c functions? Not too sure

 

Yeah the light for whether or not A/C was on rather than just the fan wouldn’t light up. It looks like it may have changed after 1998 though.

 

Try this... fuse #7 on the list
https://www.youtube.com/watch?v=rs_peO1T7vQ

 

Right on, I definitely did not take a look at this fuse box yet. I’ll do so after work and report back.
Appreciate the help!

 

So I did not find a fuse box passenger side related to this diagram, but I did find one similar under the driver side dash. Pulled the gauge fuse and it was normal, did notice corrosion on the power 30a fuse though, swapped that for a new one and no changes there also.

I then bought a recharge kit to see what pressure I had in the low line, way too much, but I guess that's because the compressor isn't on to pull any in?

So what do I do now…

 

If you have too much in the system, it won't turn on the AC.

 

I successfully ran a positive to the ac compressor clutch and I do indeed get a clicking sound from the compressor when tapping positive terminal.

Probably good to mention the car did come with aftermarket sound system, so maybe the PO loosely connected the HVAC unit, or forgot to in general. I will investigate this after work.

OR I wonder if there’s an actual AC relay that I’m unsure of it’s whereabouts

 

I would bet on the relay, as there is quite a bit of current going to that electromagnetic clutch on the compressor.

 

Any idea where I could find this relay? I've checked driver side engine bay and under the dash, then also passenger side glove department.

Also other forum are saying my compressor is bad because when I jumped the compressor clutch with the car running, it did not engage.

 

As previously mentioned above in Post #12, that same pressure switch will prevent the compressor clutch from engaging when the system pressure is too low, and too high to prevent damage to the system.
Go back and watch the video in Post #9, it seems in that post fuse #24 also affects the air conditioner system. I would watch the video and pause where you see anything that has to do with air conditioning in the far right column that describes the function of the fuse. It doesn't make sense at first glance that a fuse for the heater would have anything to do with A/C, until you think about what happens if the blower doesn't function.

 

Ahhh, maybe I try jumping the clutch again, but also the pressure switch at the same time?

also I’ve checked all fuses and relays listed in the video. They’re all good

 

You did have a high pressure reading in post #11. That would prevent clutch engagement. As you said, you could jumper the connector removed from the pressure switch, but is it worth damaging the compressor, or the expansion valve?

 

I did have high pressure, but that was because the clutch/compressor was not kicking on.

I just did more tests with pressure switch jumped and clutch manually engaged, PLUS gauge hooked up and it came back as slightly low refrigerant.
Filled it to the green mark, removed clutch jump, and still have no functions to the AC/recirculation buttons.

Worth noting the clutch only engaged and kept spinning as long as the jumper was making contact on the battery's positive terminal. I could upload videos of this, if needed.

 

Expansion valve?

 

Here's the first time I manually engaged the compressor clutch with the gauge attached.
https://youtube.com/shorts/m-uDARQQLdA?feature=share


Same thing, but compressor squealing as I am recharging freon here and there; pressure surges up and down.
https://youtu.be/yEX4FhucHJk

 

My issue is now resolved.

For anyone reading this for help for oneself, mainly experiencing no function/lights to your ac and circulation button.

For my 01 manual ac system, there was not a ac amplifier behind/under the glove department box, like the other years. The AC amplifier is built into the HVAC control unit, so swapping that out solved my issue.

Fully functional AC now! You can try to run all these tests you want, but it doesn’t really matter if you can’t electronically command your AC/compressor to be turned on. Will update with photos for better help and probably upload videos to YouTube for future 01/manual ac havers.

Thanks everyone for your effort in solving my AC issue, till next time!

first photo is typically where you could find the AC amplifier. In my case, it is integrated into my HVAC control unit.

 

Cool. Thanks for the info.

BTW, if you don't want your old board, I'd be interested in it to look and see what went bad on it.

 

Unfortunately I already tossed it out :/. Now we won't know if a simple soldering fix would have sufficed