Topic: AC Shutoff Coolant Temp Sensor - confirm please

[jssgbsn]

Just want to confirm this is the 'AC Shutoff' Sensor.

It was literally hanging by a wire for a long time and finally broke.

I'm pretty sure I don't need this sensor to drive safely.  (AC doesn't work right now anyway).

But when I do get the AC working I read this sensor will shut off the AC if the water gets too hot.

Thanks!

[jssgbsn [OP]]

Here is the pic

[emsvitil]

22R ? RE ?

Zoom out, not sure exactly where that's located on engine.

[jssgbsn [OP]]

22RE

Water Outlet Line after Thermostat. (Not attached to the intake plenum.  It comes off with the Outlet Pipe you remove to get at the thermostat.)

When I get back later I'll shoot another pic.

Can't adjust the file size from my phone.  Have to upload to computer first, then tweak it before posting.

[emsvitil]

Not part of the AC.    Looking at the manual, the AC thermo switch was optional with the towing package.

That sensor has a tab on top, not a wire coming out of it.

I think it goes to the ECU for some emission reason.     I'll see if I can figure it out.

[jrock]

I alway thought that was the temp sensor for the computer. It's a very commonly broken wire.

[jssgbsn [OP]]

I keep hearing the Temp Switches (ECU and Dash Gauge) are before/behind the thermostat not on top.  Here are two more pics a little further out for reference.

When I have seen other pics on line of this most people think it is the temp switch for the ECU, but then other people chime in and say that the ECU temp sensor is behind/before the thermostat not after. 

I'll keep looking.  In any case, drove for about 20min or so, t-stat is working, comes to temp correctly, dash gauge keeps it floating about 40% up the gauge, just a little below horizontal.

[jssgbsn [OP]]

I have a read a few times that this sensor was discontinued by Toyota and no longer available.  I'm guessing its the AC Shutoff (for towing/4x4) because of that reason.

[emsvitil]

That one...........

My wire almost broke, I put a blob of RTV on it before it broke.


By process of elimination......

There are a total of 5 possible thermo switches/sensors.

1 dash gauge: located between intake manifold plenum and cylinder head between cylinders 2&3 (really buried)
2 ECU temperature sensor
3 cold start timer switch:  2&3 are next to each other under the top hose near the outlet
4 temperature switch (4WD only)
5 AC thermo switch.

The manual shows a diagram of where 2 & 3 are.
It took me awhile to figure out where 1 (temp gauge sensor) was.
The AC section show the AC thermo switch as a tabbed sensor/switch right next to another sensor/switch behind the thermo outlet (not mentioning what the other sensor is)

So by process of elimination, the mystery switch/sensor (4) is the 4WD temperature switch.

Can't find what it does, how to test it anywhere in the manual.

I would assume the ECU does something different (richer mixture, adjust timing, ) when you get too hot in 4WD to try to help cool things down.

The switch either closes or opens when it gets hot.     

If there's enough wire remaining on it, you could see if the switch is open or closed cold, then if it changes under normal temperatures.    If you're really curious, take it out, put in boiling water and see when it changes state.  If boiling water doesn't do it, it's most likely some type of overheat switch.


You might be able to chip out enough plastic to put a solder blob on it and reattach the wire.

[jssgbsn [OP]]

Thanks man.  Sounds like other places I have read say it is either the AC Shutoff (which sounds like that is not the case based on the diagram you found) or a 4x4 Sensor.  Here is a link with a list of the temp sensors (i don't see the 4x4 one listed although I know I have heard there is one).

http://www.toyota-4runner.org/classic-t4rs/160188-complete-list-22re-sensors.html

And his youtube links are from 22reperformance for the ECU and Dash Temp sensors.

In either case, sounds like I don't need to worry about it, for now...

[jssgbsn [OP]]

You might be able to chip out enough plastic to put a solder blob on it and reattach the wire.

The wire is too short.  I would have to splice extra wire on first, probably have to take the connector apart also.  Rather not do any of that if it's just that 4wd temp sensor.

But thanks for trying to help figure it out

[emsvitil]

If you have to worry about visual smog tests, put a blob of RTV to hold the wire on so it LOOKS ok.........

[jssgbsn [OP]]

No smog in FL.  Still rather be in CO though.

Thanks again

[emsvitil]

Found out what it does.

It raises fuel pressure when engine is over 230

Described as temp switch #2 here:

http://www.22rte-trucks.com/simplemachinesforum/index.php?topic=31.0


Then check page 9 here: (read page 8 first)

http://www.autoshop101.com/forms/h22.pdf

So in addition to heavy load, high speed; it looks like high temp for 4wd