edeslaur

Hi everyone,

87 4Runner Turbo, AT.

AC button lights up and the compressor doesn't always kick on. When it does, blows very cold, not a refrigerant charge problem.

It will come one sometimes when I stab the switch multiple times, sometimes when I hit a bump. Lately it's been coming on less rather than more.

It also stops working that way sometimes too (but usually stays working when it's working)

Any suggestions where to look before I tear my dash apart looking for a bad connection, only to find out it's something easy?

Thanks

rworegon

Check for a loose wire at the compressor.

edeslaur

Done.

BMcEL

Done as in fixed? It's most likely in the circuit between the amplifier and compressor...if you're blowing the AC fuse it's a short, otherwise it's an intermittent open.

edeslaur

I wish! Done as in connections checked.

I just realized the RPMs aren't climbing either.

No fuse issues.

I'll break out the meter and wiring diagram and hope I'm not getting too far jnto the dash. AC would be real nice right about now.

BMcEL

If the AC light comes on and the pressure is good but it's not idling up, start by testing the low pressure switch and the VSV. Procedures are in the FSM. As far as tearing into the dash, all you need to do is pull the glove box out. Good luck and keep us posted.

ChefYota4x4

iTrader: (5)

Watching, ..... my only issue is the idle doesn't rise when I switch it on.. Runs cold, R12, all new O-rings, Drier, ..... I replaced the AC Idle up VSV on the Valve Cover with one from the Jyard, ....nuttin. Would love to know if you get the idle up fixed, let us know. Best wishes on the intermittent switch issue.

I've heard that the button in the dash can wear out the contact..... have you tried bypassing that switch with another cheapo switch for now, just to check? (Two part switch, for light and power, right?)

93YotaGuy

Has the expansion valve ever been replaced? If it is clogged it could be the cause for it to work intermittently. I have an extra Denso expansion valve that I could sell you if you need it for cheap. I pulled my AC from the junkyard a couple of years back and they changed the expansion valve after 93 so I have the smaller one that I could never use just collecting dust in my garage.

I would also look at the amount of air you are getting through the condenser. I say this because when I first installed the AC my black magic fan would cause it to run intermittently due to the fact that it would only turn on when the motor was above a certain temperature. I wired an AC connection that keeps it on when the AC is on and fixed the problem.

Another cause could be that you may not have enough R12 in the system. I'd check that as well. I believe it's 40 lbs per square inch? Or something like that. Don't quote me on that.

I started a thread on my AC issues in regard to the expansion valve here. Check it out.

https://www.yotatech.com/forums/f116...issues-186810/

Good luck! Hope this helps.

93YotaGuy

Chef,

Have you checked to see if the vacuum is working correctly? Maybe you have a leak?

Also, what is your idle set at? Is it low enough to where it would raise the RPM when you have the AC on but not too high enough to where it would mess with the computer and cause it to run in a loop?

ChefYota4x4

iTrader: (5)

Thanks, 93(sorry for the highjack, Ed! lol)

It's idling like butter at 750, FINALLY(trust me, it's been a ROUGH YEAR of chasing of tail....only to have to START OVER WITH ANOTHER MOTOR! Lol....) .....Almost no miss, and what's there is probably the CAM.... (TEEENY!LOL).

'Vacuum', meaning, the valve with the white screw on top? I cleaned that out like new when I rebuilt last year, the first time.... and it's clean, maybe half way out. If you meant the black binary valve(VSV) on the valve cover toward the front? Not sure, I got it from a yard, ......and when I push on the blue button in the dash, she kicks right on, just doesn't idle up....Rather, idles down to around 550rpm. Strange thing though...If I sit long enough at idle at a stop?>>>> It WILL come up, just never enough, and CERTAINLY not to like 800 or whatever it should be. The switch on the top of the compressor...that's just to kick on the clutch, right? That connects to the vsv one on top through the harness somewhere, etc., right? Kinda at a loss, lol.

anyway, ...I wont highjack anymore, maybe you could chime in on my build thread in my sig? lol.... And honestly? I'm almost never running it at idle...just on my trips through the high sierras or desert into AZ, etc. So unless it's possibly going to damage something, I'm not too concerned....just curious(plus, would be nice for it to work like it's supposed to, I suppose, eh? hahaha) Thanks again 93!

Back to you, ED! Again, sorry, not like me, ...didn't intend for that, but I'M GRATEFUL! LOL.

ToyoTech559

check your relay

ChefYota4x4

iTrader: (5)

OOOH, yeah, ED, ..... when you flick it on, feel in the dash next to the box on that AC relay.... if it gets REAAAAAAAAALLY hot, it could be a sign it's the cause, ya know?

Wait, you're speaking to ED, not me, right Toyo? hahaha.

Anyway, ...the Jyard charged me 3$ for that relay...and I KNOW it works, tested it in my buddy's rig when trying to diagnose his gremlins! lol.

ToyoTech559

i was talking to op

but for you chef. does your a/c work when driving? just at idle the air isnt cold? at idle while holding the throttle up to like 1500, does it get cold and stay cold? i know you replaced your a/c idle up vsv but do you know its good? also there should be an adjustment screw for the a/c idle up as well.

im not good at diag older cars/trucks. only been at it for the past 5 years and well i just dont see or work on any older cars/trucks

ChefYota4x4

iTrader: (5)

Hey Toyo, .... reminded me to bring this up in my build thread, too, thanks! lol.... I'll go there and do that now.

ED, HOW'S IT GOING?

edeslaur

Hijack away, Chef, I'm learning a lot from this thread. Didn't get to it this weekend, got sick instead. Daughter's driving it today (high 90s), and I have her RAV4 (needed an alignment, was eating the new tires), so I'll hear about the AC when I get home.

I'll break my meter out and check it, probably this weekend. Can never get home before 8 during the week, by then I'm knackered.

So... back to Chef's problem!!

ChefYota4x4

iTrader: (5)

Hahaha...

Thanks for being forgiving, ... not like me to do that(well, not the highjack, ....The rambling is TOTALLY normal! LOL)

Far as the "Chef's Problem"... Oh boy, let's see, my first ex was a real doozy, ...almost killed me, and I ......................................OHHHHHH, yeah, the AC.

Ok, lol....... NOT SURE! Grrr! I'ma pin it down though. But first, ...need to remind that:>>>

My issue is NOT the AC(or clutch in essence) kicking on and off. My AC comes on when I push the button, runs cold at even a stop light in idle..... But two things;

1. It DOESN'T WANNA idle up when at an idle/stop. It WILL, for a second, idle at the same rate, 750rpm(which, I KNOW, means that the system is kicking in more vacuum to take up the pull created by the compressor)..... But SECONDS LATER, 3-5 seconds, ...it drops off to 500 or so. Sometimes coming up again to 600? Never to 750 again.

2. I'm also having an issue, whether using the heat or AC..... with the FAN. When I try to use the fan motor at the first setting(lowest)...it WILL NOT BLOW! Got some ideas on that to try, ...not sure when I'll be able to actually try it. LOTS of stuff to do today.

I'll keep ya updated. I'm still thinking you've got a lil issue with a bad contact in your button/switch, ED! That doesn't mean much as I'm JUST LEARNING, lol...but hey, I did change every seal in the system, new drier, found R12, pulled all stale air out, held a 'pulled down to 30"s' over night test, ......then charged it with a pro, ......and I think it's pretty COOL! lol... seriously, that was a VERY lame pun, but you get the point. I'm VERY happy, and I don't take it for granted after 14 years without AC in ANY vehicle I've had!

markfagus

from what I have read on this forum, the blower motor not working at lower speeds is a resistor issue.

ChefYota4x4

iTrader: (5)

Hmmmmm, resistor as in the relay looking things by the blower motor?

Anyone have any idea/schematics on where these resistor doohickiemadoers are? lol.

BMcEL

The resistor(s) are under the dash...there is a write-up on here somewhere. The contacts in the switch can also fail.

ChefYota4x4

iTrader: (5)

In the actual "1-2-3-4" level, lever switch, the one for fan control? Just making sure you didn't mean "the Blue Button" switch, ahaha. Thanks, BMcel