Explain what the AC Amplifier does ?

krzyabncanuck

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Can anyone explain what it does ?

I just had to adjust mine to get the ac to work. The little knob that turns on it. My clutch would not engage until i turned the knob. How far should it be. Right now i have it turned all the way. but I am wandering if i should just turn it till the clutch kicks in. Or is there a temp for it to be working on ?

Thanks all.
 

krzyabncanuck

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I have the FSM and it really does not say what it does or what it should be set at. Least i could not find it.
 

kevinmrowland

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The chassis manual has a nice section on the AC system, even diagrams the circuit for you. the "magic blue knob" does exactly as mentioned, adjusts when the amp will let the clutch engage in regards to RPMs.
Clockwise=lower RPM
CCW=higher rpm required to run the AC.
The amp gets a signal from the coil, same wire as the tach, that it reads for RPM.
Thermister and pressure switch functions are also controlled in the AMP, it all come down to telling the compressor when to run and when to shut off.
Just remember that to bypass the entire amp just jump the yellow wire to the black with white wire and the clutch will engage when the AC button is pushed, disengage when the button is out.
 

krzyabncanuck

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Thank you very much Sir for breaking it down for a grunt like me.

Let me ask this then. Do i just turn it until the compresser kicks on or what is the best way to adjust it ?
 
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You people! Always complicating things!

An AC amplifier amplifies the air conditioner, silly.:D
 
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ok im actually glad this was asked...

i have in my possesion right now a 88 FJ62 (good friend of mines truck) and i was driving I just got done doin an a/c conversion for him now 2 days later driving back to work from lunch a/c blowing full blast (at 38 deg. F on a 90+ day) i hear a "POP!" ish sounding noise and BAM! no blower a/c clutch disengauged and then now the little "a/c light" does not even come on.

What the hell happened?
I know mechanics, I know suspensions, I also know a/c....
I do NOT know electrical very well. I check all fuses and relays and they were all good. So i bust out the repair manual and find a wiring skew... And im not really sure how to read it. It is a haynes manual. I in my automotive experience beleive it to be the a/c resistor but i could be wrong. everything else on the truck work except the blower and the little light that kicks on when a/c button is engauged, also thus meaning the a/c clutch is not engauging.

Anyone give me a lesson on electrical for dummies or maybe had this issue and point me correct direction?
 

kevinmrowland

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Fuses are one thing, but did you check the 30a circuit breaker next to the fuse box? The diagram on the back of the cover will list it for the blower but it also controls power supply for the AC.
More importantly you need to figure out why, and it is too early for my brain to work yet.

The above amp information pertains only to an FJ6o AC setup, the 62 is slightly different, no presence of a magic knob since the amp tells the ECU when it want to turn on and the ECU tell the motor to speed up. Pin locations function and wire colors are the same, the 62 has an additional splice into the starter circuit to disengage the clutch when the starter is turning the motor.


*EDIT* I can't remember if the 62 circuit breaker location is the same as the 60, can anyone verify?
 
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kevinmrowland

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Thank you very much Sir for breaking it down for a grunt like me.

Let me ask this then. Do i just turn it until the compresser kicks on or what is the best way to adjust it ?

Well that is the problem with adjustable systems, they are adjustable.
The point of the blue knob is to make sure the AC system does not lug the motor out and to disengage the clutch if the motor is not spinning (like when you go and start it, it would make the starter work harder if as soon as the key was on, the clutch engaged)
The blue knob has a range, I think it is 600-1200 rpm. My advice would be turn the AC on, make sure the engine sounds healthy, not too high rpms, not too low (adjust this with the AC idle up on the front face of the carb, little adjusting screw on the linkage will change rpm when the VSV is open) Then go turn the blue knob till the AC cuts off, then turn it back past that point a bit and it should be good.
 
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Has anyone replaced the A/C amplifier?

Is it available new or rebuilt OEM Toyota?

I have 2 problems:

1. My A/C idle up VSV stops working after the A/C has been on for a minute or 2. I tested the valve itself and it was working fine. When I first turn on the A/C, it always applies vacuum and the idle increases to 900-1000 RPM. After a minute or 2, it kicks off. I think this is related to the A/C amplifier tripping the signal. Adjusting the blue knob doesn't seem to help. Grant here in TX said you could direct wire the VSV from the compressor to correct this problem.

2. Cruising down the highway with A/C running, it will be good and cold and the air blowing well. All of a sudden, the fan will quit blowing or act like it's "frozen up" with only a small amount of air coming out the vents and there will be a lot of really cold condensation down on the ducts. Is this the blower going out, another A/C amplifier problem, or something else?
 

Dynosoar

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Note: With a V8 conversion (or Diesel) the signal from the coil (or no coil in a Diesel) will make your A/C Amplifier work strangely. I believe (not positive) that Diesel Cruisers have a signal generator. I also believe that you can do a inline conversion similar to the one you can do to make the tach read correctly with a V8 (potentiometer) LINK

All that said my A/C works great with the V8 even with the 8cyl. signal from the coil.


Dynosoar:zilla:
 

kevinmrowland

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Has anyone replaced the A/C amplifier?

Is it available new or rebuilt OEM Toyota?

I have 2 problems:

1. My A/C idle up VSV stops working after the A/C has been on for a minute or 2. I tested the valve itself and it was working fine. When I first turn on the A/C, it always applies vacuum and the idle increases to 900-1000 RPM. After a minute or 2, it kicks off. I think this is related to the A/C amplifier tripping the signal. Adjusting the blue knob doesn't seem to help. Grant here in TX said you could direct wire the VSV from the compressor to correct this problem.

2. Cruising down the highway with A/C running, it will be good and cold and the air blowing well. All of a sudden, the fan will quit blowing or act like it's "frozen up" with only a small amount of air coming out the vents and there will be a lot of really cold condensation down on the ducts. Is this the blower going out, another A/C amplifier problem, or something else?

Does it stop working in conjunction with the AC clutch disengaging?
It should not kick up the idle continuously, just when the clutch is engaged.
You can just jumper the VSV from the clutch wire, it will have the same function.

The function of the fan is separate from the AC system and the AMP, other than the blower switch providing power to the AC button and amp.

There are a couple semi-recent threads about refreshing the blower motor, that might fix you up.



Dynosoar said:
Note: With a V8 conversion (or Diesel) the signal from the coil (or no coil in a Diesel) will make your A/C Amplifier work strangely. I believe (not positive) that Diesel Cruisers have a signal generator. I also believe that you can do a inline conversion similar to the one you can do to make the tach read correctly with a V8 (potentiometer) LINK

All that said my A/C works great with the V8 even with the 8cyl. signal from the coil.
This is true with the 60 series, but not the 62. The 60 series AMP receives the coil signal as a go-no-go, the 62 sends a signal to the ECU to tell the engine to speed up, and has a spur wire from the starter magnetic switch that tells it to disengage the clutch when the starter is engaged.
You can get signal translators that convert the coil pulses to operate the way you want so that a 60 amp gets the pulse signal it will recognize, or you can drop a 62 amp into the 60 AC. If you pull the black coil wire from the amp plug the 62 amp will operate the AC correctly even with the absence of a coil pulse.
 
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Does it stop working in conjunction with the AC clutch disengaging?
It should not kick up the idle continuously, just when the clutch is engaged.
You can just jumper the VSV from the clutch wire, it will have the same function.

Not that I can tell. In fact, I don't know if the compressor does cycle on and off, which is another reason I think the amplifier is not working. It also may be why it freezes up when I'm on the highway. I guess I need to pull out the FSM and trouble shoot.

The function of the fan is separate from the AC system and the AMP, other than the blower switch providing power to the AC button and amp.

There are a couple semi-recent threads about refreshing the blower motor, that might fix you up.

I'll look into the blower threads. Thanks.
 

kevinmrowland

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Not that I can tell. In fact, I don't know if the compressor does cycle on and off, which is another reason I think the amplifier is not working. It also may be why it freezes up when I'm on the highway. I guess I need to pull out the FSM and trouble shoot.
The function of the idle up inside the amp is relatively simple, if the clutch is engaged-the idle up is activated.
Now the clutch being engaged, that is more complicated. The amp gets signals from the thermister and pressure switch that say it can turn on and off. You can tell if the clutch is disengaging by simply opening the hood and watching it for a minute, it should not take long for it to build pressure, when it does the clutch on the front of the AC pump should separate. The ice up and unwillingness to turn off would indicate a faulty thermister (cheap part but the system needs to be drained)
Time to get out the FSM. :cheers:
 
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The chassis manual has a nice section on the AC system, even diagrams the circuit for you. the "magic blue knob" does exactly as mentioned, adjusts when the amp will let the clutch engage in regards to RPMs.
Clockwise=lower RPM
CCW=higher rpm required to run the AC.
The amp gets a signal from the coil, same wire as the tach, that it reads for RPM.
Thermister and pressure switch functions are also controlled in the AMP, it all come down to telling the compressor when to run and when to shut off.
Just remember that to bypass the entire amp just jump the yellow wire to the black with white wire and the clutch will engage when the AC button is pushed, disengage when the button is out.

This is just what I was looking for! My AC works now! :)Thanks!
 
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Bringing up the past! I think this is just what I need... Where exactly is this AMP location? inside? under the hood?

I don't have a FSM, and having a hard time trying to find it.

Thanks!
 

Tapage

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amp in diesels need tacho signal .. as same as gassers .. the difference here it's picked directly from the tacho sender ...
 
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Does my tach have to be functional for my ac clutch to kick in? or does it feed off the distro cap where the tach hooks up to? or is both of these irrelevant.
 
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