Mg clt clutch relay location to fix ac

dripdry

New member
Hoping someone can help....I was told this was located behind the glove box. I tore out the glove box and do not see a relay that just pops out. I only see different connectors with wires going to them. I always thought a relay could be just pulled out and replaced? My air conditioning commpressor does not kick on anymore and I am hoping I can replace this relay to fix the problem. Any help would be appreciated!!
 
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You probably need a re-charge, there's a low pressure sensor that won't allow the compressor to kick on when the system is low on refrigerant. The relay should be in the fuse box under the hood but I don't believe that is your problem.
 
IM having the same issue with mine. I bought a relay from autozone but cant find where it goes for the life of me. It's no a/c relay port on the fuse box under the hood or in passenger compartment. Im lost. Any help would be appreciated!
 
Guys.. 95% of the time the relays are fine. These rigs are 18 plus years old. The condensers develop leaks, compressors seals go and leak the refrigerant out. If the system is low or out of refrigerant. The safety switches will open and the compressor will not kick on.
 
Normally, I would attribute this to a leak like some of you guys stated. But the ac was ice cold then went straight hot. And I have no sign of oil/freon anywhere under the hood. And it still may be a leak, but wanted to try the $17 fix before I give the ac guy a lot more $$$. Still cant find where this relay goes.
 
Normally, I would attribute this to a leak like some of you guys stated. But the ac was ice cold then went straight hot. And I have no sign of oil/freon anywhere under the hood. And it still may be a leak, but wanted to try the $17 fix before I give the ac guy a lot more $$$. Still cant find where this relay goes.
What year is your 4Runner? Do you have manual or automatic (digital display) climate controls?
 
The magnetic clutch can fail and thus instantly your AC pump will not work..

Possible your high or low pressure safety switches fail and not engaging the magnetic clutch on the compressor.

Relay possible but very rare.

All this takes is a small rock to pinhole your condenser and all your freon gone and you may not see it.


Snap a set of gauges on to verify you have correct pressure in the system as it rules that out. :)

Sent from my SM-J337V using Tapatalk
 
The magnetic clutch can fail and thus instantly your AC pump will not work..

Possible your high or low pressure safety switches fail and not engaging the magnetic clutch on the compressor.

Relay possible but very rare.

All this takes is a small rock to pinhole your condenser and all your freon gone and you may not see it.


Snap a set of gauges on to verify you have correct pressure in the system as it rules that out. :)

Sent from my SM-J337V using Tapatalk

Thanks for the info. Will a pressure gauge read accurately without the compressor turning? I'm fairly competent shade tree mechanic but the ac stuff is out of my wheel house.
 
Thanks for the info. Will a pressure gauge read accurately without the compressor turning? I'm fairly competent shade tree mechanic but the ac stuff is out of my wheel house.
I don't think there is a relay for your ac. I'm basing this off a 2000 wiring diagram for a manual ac.

Hooking a set of gauges to it even without the compressor working will let you know if you have enough refrigerant for the pressure switches to complete the circuit. You should have between 75-100 psi on both sides depending on ambient temp.
 
Thanks for the info. Will a pressure gauge read accurately without the compressor turning? I'm fairly competent shade tree mechanic but the ac stuff is out of my wheel house.

When in doubt, RTFM. If gas is too low for compressor to run, you will see low and equal pressure on both sides. I think low pressure switch kicks in about 25psi.

http://www.teamtoyota4x4.org/archivio/1996%20to%202002%20Toyota%204Runner%20Repair%20and%20Wiring%20Manuals/techinfo.toyota.com/ileaf/02toyrm/02toypdf/02rmsour/2002/024runne/ac/acsy/ovi.pdf

There us indeed no A/C relay in the manual A/C system, That function is handled by the A/C Amplifier, which is Toyota speak for the ECM for the A/C system, which is not a $17 part and rarely goes bad. You can return that relay.

http://www.teamtoyota4x4.org/archivio/1996%20to%202002%20Toyota%204Runner%20Repair%20and%20Wiring%20Manuals/techinfo.toyota.com/ileaf/ewdtmc2/ewdtmpdf/ewdsourc/2002/024runne/systemci/057acman.pdf
 
Last edited:
Is it too late to revive this thread? Manual AC system, 2001

I can’t figure this out. Basically getting no a/c or recirculating power to the control unit (No lights at all from those two buttons.)

Jumped pressure switch like suggested, but no changes. Clutch does not engage

I pulled a relay from a 1997 to swap in, but turns out I don’t have one.

I’ll try to get my hands on some pressure gauges to test high and low.
4Runner.com ?01 A/C - YouTube

More context can be found at '01 A/C does not kick on at all (including green light) | Toyota 4Runner Forum [4Runners.com]
 
Possible bad pressure switches or no refrigerate. Magnetic clutch is either on or off and you can supply battery voltage to it to enable it...:)

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Possible bad pressure switches or no refrigerate. Magnetic clutch is either on or off and you can supply battery voltage to it to enable it...:)

Sent from my SM-A536V using Tapatalk

Since I jumped the pressure switch, doesn’t that bypass the safety measure, or would it still not kick on if I had low refrigerant?

Seems like the next steps are to try recharging Freon and testing clutch
 
Since I jumped the pressure switch, doesn’t that bypass the safety measure, or would it still not kick on if I had low refrigerant?

Seems like the next steps are to try recharging Freon and testing clutch


The clutch goes bad as well and some have a thermal safety switch the eventually fails.


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So I did not find a fuse box passenger side related to this diagram
fuse-jpg.131269
, 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, so what do I do now…have it vacuumed out?
94a58120-8760-4cc1-8e11-c67b076c739d-jpg.131328

f9f14c18-8a5b-44cf-bcd9-8da817b0fc7f-jpg.131330

8137a014-53d6-407c-a9d0-865fbef12d16-jpg.131331

975b1fed-d9e8-4c9b-8161-76b2f0f09f7a-jpg.131332
 
So I did not find a fuse box passenger side related to this diagram
fuse-jpg.131269
, 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, so what do I do now…have it vacuumed out?
94a58120-8760-4cc1-8e11-c67b076c739d-jpg.131328

f9f14c18-8a5b-44cf-bcd9-8da817b0fc7f-jpg.131330

8137a014-53d6-407c-a9d0-865fbef12d16-jpg.131331

975b1fed-d9e8-4c9b-8161-76b2f0f09f7a-jpg.131332
The gauge on that can is meant to be used when the ac is working. You are not over charged.
 
Since I jumped the pressure switch, doesn’t that bypass the safety measure, or would it still not kick on if I had low refrigerant?



Seems like the next steps are to try recharging Freon and testing clutch
The safety switches are there for 2 reasons. It's too low of refrigerate and too high pressure.

So if the system is not in the proper pressure, the pump will not kick on. Hence, safety pressure switches. :)

Sent from my SM-A536V using Tapatalk
 
For a test. What happens when you apply battery voltage to the ac magnetic clutch? You can even to this with everything off. Does it click?

With the engine running, does the magnetic clutch engage, and is the pressure on the low side dropping?

Might be able to rule that out as good or bad.

Sent from my SM-A536V using Tapatalk
 

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