Thermostat I.D. sensors. What do what?

[bazeng]

hey guys
can anybody identify the sensors?

(WHAT EACH SENSOR IS FOR)

thanks

1.
2.
3.
4.

thanks
(just want to know what i can get rid of)

 

[Jason G.]

The #1 single prong one is for the gauge in the dash.
One of the 2 prong ones is for the ECU and the one on the top above the t-stat (#4) is for the AC.

The US models only have those 3, so I'm not sure what your #3 sensor is used for.

 

[atc250r]

One of the single wire connectors is for the gauge and one will turn both fans on high speed if the vehicles temperature exceeds 225*F. I'm not 100% sure on the temperature but that's what it does. If you ground the wire that goes to it then both your fans will go on at high speed immediately.

John

 

[bazeng]

would these single wire sensors be the same?
ie. if i were use either plug for either sensor, would they both give the same values?

or is each sensor (single wire) specific?

 

[atc250r]

No they are different. The one that goes to the gauge changes resistance as temperature changes and the fan switch simply grounds the wire when it sees a certain temperature. I had those two crossed when I first bought my car and installed a new engine. The car wouldn't start with the wires crossed. It doesn't make sense but that's what happened. The one on the back of the thermostat housing is for the fans.

John

 

[Jason G.]

IIRC, the switch to turn the fan on is in the lower right side of the radiator. I only have 3 sensors on my t-stat housing. /ubbthreads/images/graemlins/confused.gif

 

[bazeng]

the thing is they both have the same threads!
yikes!!

what to do now, on of them is longer than the other...
one is about 1cm long (cylinder shape)
the other is about 2cm's long (cylinder + a rounded piece on the end..

is there anyway to identify?

multimetre i guess?

 

[atc250r]

Yeah, I wish I could help you there but I'd guess a multimeter is your best bet. Jason, the regular fan switch is in the bottom of the radiator but the one on the t-stat housing is more of an emergency switch where if all else fails that should turn all the fans on high. When the resistor went bad in each of my GVR4's the only time the fans would come on is when that sensor turned them on. The scary thing is that the stock temp gauge is such a POS that it never really went much higher than normal when that happened /ubbthreads/images/graemlins/ooo.gif.

John

 

[3Diamond]

Ok some of the US cars came with a vacuum switch as well, but thats beyound point.

ECU Sensor:

Gauge sender (one that shows temp):


Fan temperature Switch:


The AC swithch is the one on top. Couldnt find a pic of it. The fan switch is also present at the bottom of your radiator. IIRC there are four fan speed controls for 2 fans. One is on/off by rad switch; second on/off by AC on/off; third should be HIGH by ecu; and the final is the emergency by that switch, as someone else said it turns both fans on full.

 

[bazeng]

great!
thats what i needed..
thanks for that

 

[Jason G.]

Hmmm, I don't have the 4th sensor on my car. Hell, I don't even have wiring for it. Not that it matters that much since my fan is hard wired anyway.]

Edit: I do have a vac fitting like above in what looks like to be where the fan switch is.

 

[3Diamond]

Vac fitting should be for EGR valve (unless its a cali car, in which case its a solenoid from ECU).

 

There's always been confusion on what the hell is what.
The sensor in the back(facing firewall) is the "emergency" switch that turns both fans on high.
The front has 3 sesnors.The bottom left is the ECU sensor(2 wires).Next to this sensor(right) is the temp guage(single wire).Above the ECU sensor facing forward toward the radiator is the EGR vac switch.The switch facing upward on the top of the thermo housing is the A/C switch.
Nuts!

 

[atc250r]

Cruce hit it dead on! There cannot be any confusion after that unless the non USDM cars are different.

John

 

The hose fitting next to the sensor marked #2.
Where does it go to?


:edit: never mind it goes to the liquid oil cooler that i no longer have.