coolant temperature switch

[93spoolin]

ok so I read in an older post about when the coolant temp sensor went out that they just grounded the 2 wires to the thermostat.has anyone else done this..can you do it to the ct switch


also the reason i was asking about this is because I went to napa and autozone and took the switch and they looked them up and told me that wasnt what it was.im confused.my car is at my buddys shop so i cant go look at where it came out.they said it looked like the fan switch. i looked up pictures of the fan switch and I dont think they look alike. is there anyway yall can describe the coolant temperature switch,sensor and the fan switch.or just post pics,i hate parts stores

 

[rocafellafw]

I'm in the process of trying to test my coolant temp SENSOR. The sensor goes to your ECU, the Switch goes to your gauge I believe. Why do you need the fan and or sensor ?

 

[93spoolin]

naw i dont know what it is...im trying for someone to get some pics of the sensor,switch,and fan switch...

 

[rocafellafw]

Here this is from my thread, this is a pic of all the switches/sensors on a 1g t-housing:

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I"think" the blue dot goes to the stock gauge, the yellow is the 1G Coolant Temp Sensor that goes to your ECU, Red idk but I tapped it for my aftermarket Temp gauge, Idk what green used to be but the my previous owner tapped it for the 2G Coolant Temp Sensor which is what I'm hoping replacing it fixes my running rich issue.

 

[EagleTSIawd]

There are two temp sensors, one for the ecu (which decides when to turn on the fans) and the other for the cluster which moves the needle up or down. The one for the ecu has 2 wires and the other for the cluster only has one.

 

[93spoolin]

the green almost looks like the one i have...it has a plug on it with 2 wires...im already fed up with dsm!!and mainly the dumbasses at autozone..come someone tell me what the green is?

 

[nytescion]

green is for the ecu. tell the ecu what temp the motor is at and supplies fuel accordingly when starting car

 

[93spoolin]

ok well what is it?i havent got to drive my car yet but my buddy that sold it to me said it was stuck in cold mode. so it was spitting more gas.im just trying to get this done so it will be one less thing for me to do

 

[93spoolin]

oh he said it will run but just run like crap i guess

 

[redyute1]

Here this is from my thread, this is a pic of all the switches/sensors on a 1g t-housing:

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I"think" the blue dot goes to the stock gauge, the yellow is the 1G Coolant Temp Sensor that goes to your ECU, Red idk but I tapped it for my aftermarket Temp gauge, Idk what green used to be but the my previous owner tapped it for the 2G Coolant Temp Sensor which is what I'm hoping replacing it fixes my running rich issue.

This cant be a 1g housing cause the 1g housing has only three sensors,single wire is for the guage,2 wire is for the ecu (coolant temp sensor),then on top of the tstat housing is an other 2 wire sensor this is for the ac module if your ac dont work then dont worry about it

 

[93spoolin]

well i got my old one right here and it is a white end on it where the harness clips in.also its sorta oval.ill try to get pics tommorrow of it.i know its a shitty way of explaining it but hopefully someone knows what in talking about

 

[nytescion]

This cant be a 1g housing cause the 1g housing has only three sensors,single wire is for the guage,2 wire is for the ecu (coolant temp sensor),then on top of the tstat housing is an other 2 wire sensor this is for the ac module if your ac dont work then dont worry about it

you're right. I'm sorry i looked at the picture too fast.

 

[93spoolin]

whats the name of the green one?

 

[nytescion]

If you have a first generAtion there is only three sensors . One for gauge this one will be on top of the housing. Then one that has two prongs perpendicular to each other this is for ecu.then a one prong connector this is for fans.

 

[93spoolin]

yeah i have a 1gen.the one i got out has 2 prongs side by side straight

 

[redyute1]

If you have a first generAtion there is only three sensors . One for gauge this one will be on top of the housing. Then one that has two prongs perpendicular to each other this is for ecu.then a one prong connector this is for fans.

WRONG WRONG WRONG the fans are controlled by the therno switch which is located at the bottum of the radiator next to the lower hose.!g's carry the red yellow and blue,but in that pic the red one on the 1g is a 2 pin one with a whiteplastic end which would be for the ac

 

[1990AWD]

WRONG WRONG WRONG the fans are controlled by the therno switch which is located at the bottum of the radiator next to the lower hose.!g's carry the red yellow and blue,but in that pic the red one on the 1g is a 2 pin one with a whiteplastic end which would be for the ac

Correct!!

On 1g cars, the power comes from the ignition, through the coil part of the relay, to the thermo switch on the rad, and then to ground. When the thermo switch activates, it allows current to flow through to ground, therefore activating the relay and sending power directly to the fans. Haynes manual has the schematic if you happen to have it.

 

[nytescion]

WRONG WRONG WRONG the fans are controlled by the therno switch which is located at the bottum of the radiator next to the lower hose.!g's carry the red yellow and blue,but in that pic the red one on the 1g is a 2 pin one with a whiteplastic end which would be for the ac

I stand corrected.

 

[pyv93awd]

Not trying to steal this thread, but I dont see the reason to start another thread on the same topic.
Well to make it simple I have 1993 tsia awd and my radiator fan doesnt work on its own. I had it connected to a switch, but it got too hot and broke the switch and likes to drain a lot of battery power. I replaced the thermo switch on the radiator and the fan still doesnt come on when it's hot.
The fan will come on if I use a jumper wire and connect the top-right and bottom-left pins of the Radiator Fan Relay socket. This is how i controlled the fan from a switch, but it runs too much current through. What other problems will keep my fan from turning on? I have to drive my car to school and I dont want it to keep over heating past 230degrees while Im in traffic at school. Any help will be much appreciated as I know very little about electrics on my car.

 

[Kickerbeast]

Op - The basic rule is if there are two wires it is the temp sensor for the ECU. The ECU needs to have a dedicated line to and from the sensor, they don't just ground it through the chassis, at least not an important sensor that will have a variable resistance like the Coolant temp sensor.

Not trying to steal this thread, but I dont see the reason to start another thread on the same topic.
Well to make it simple I have 1993 tsia awd and my radiator fan doesnt work on its own. I had it connected to a switch, but it got too hot and broke the switch and likes to drain a lot of battery power. I replaced the thermo switch on the radiator and the fan still doesnt come on when it's hot.
The fan will come on if I use a jumper wire and connect the top-right and bottom-left pins of the Radiator Fan Relay socket. This is how i controlled the fan from a switch, but it runs too much current through. What other problems will keep my fan from turning on? I have to drive my car to school and I dont want it to keep over heating past 230degrees while Im in traffic at school. Any help will be much appreciated as I know very little about electrics on my car.

Did you try replacing the relay? Also, did you try using the switch to turn the relay on instead. That way you don't burn up the wiring while you are fixing the actual problem.

 

[1990AWD]

Not trying to steal this thread, but I dont see the reason to start another thread on the same topic.
Well to make it simple I have 1993 tsia awd and my radiator fan doesnt work on its own. I had it connected to a switch, but it got too hot and broke the switch and likes to drain a lot of battery power. I replaced the thermo switch on the radiator and the fan still doesnt come on when it's hot.
The fan will come on if I use a jumper wire and connect the top-right and bottom-left pins of the Radiator Fan Relay socket. This is how i controlled the fan from a switch, but it runs too much current through. What other problems will keep my fan from turning on? I have to drive my car to school and I dont want it to keep over heating past 230degrees while Im in traffic at school. Any help will be much appreciated as I know very little about electrics on my car.

I had the exact same problem. I replaced the relay and it worked while idling, but then the relay would burn up when I drove. The best solution I could come up with was having the fan run constantly as long as the ignition switch was on. If you don't mind that, you can do what I did and just ground the wire sending power to the thermo switch.

 

[pyv93awd]

The relay still works. I swapped it with the headlight relay and the headlights work fine so I never went and bought a new relay.

Well it's getting cold here, so I dont want the fan on while it's trying to warm up, so I thought about using the switch to turn on the relay, but not too sure about I would go about this. Would I just have the wires squeezed in and just push the relay ontop of the wires. So when I turn on the switch, it'll be in contact with the relay and where the relay goes into? Sorry, noob at electrics here but that's what I thought of, .

 

[1990AWD]

The relay still works. I swapped it with the headlight relay and the headlights work fine so I never went and bought a new relay.

Well it's getting cold here, so I dont want the fan on while it's trying to warm up, so I thought about using the switch to turn on the relay, but not too sure about I would go about this. Would I just have the wires squeezed in and just push the relay ontop of the wires. So when I turn on the switch, it'll be in contact with the relay and where the relay goes into? Sorry, noob at electrics here but that's what I thought of, .

If you want to use a switch to control your fan(s), you could tap into terminal #2 on the relay, run that wire to a switch, and then from the switch to ground. By doing it this way, you would be able to turn on or off the fan(s) by using the switch as long as your ignition key is on.

In fact, this is such a good idea on my part, I'm going to do it.

 

[4g63eagle]

If you want to use a switch to control your fan(s), you could tap into terminal #2 on the relay, run that wire to a switch, and then from the switch to ground. By doing it this way, you would be able to turn on or off the fan(s) by using the switch as long as your ignition key is on.

In fact, this is such a good idea on my part, I'm going to do it.

could you please explain how to do that in a little more detail as far as what relay the one on the passenger side and if so it has four pins in what direction are you starting in for your #2 my fans wont turn on either and i know my fans work from jumping them at the relay and the thermo switch and ive spent close to 200 bucks and my fans still wont turn on and your idea sounds like a great solution and really easy for me thanks

 

[1990AWD]

could you please explain how to do that in a little more detail as far as what relay the one on the passenger side and if so it has four pins in what direction are you starting in for your #2 my fans wont turn on either and i know my fans work from jumping them at the relay and the thermo switch and ive spent close to 200 bucks and my fans still wont turn on and your idea sounds like a great solution and really easy for me thanks

Well to help you understand this better, I'll explain how the fans are supposed to work. There are two seperate circuits. The first has power coming from the ignition switch when you turn the key on, it goes through the coil on the relay, down to the thermo sensor and to ground. The second has power coming from the battery, through the switch on the relay and then the fan motor and to ground. When the engine is cold, the thermo switch is open, and therefore there is no current flow, therefore the relay is not activated, and hence the fans don't come on. When the rad reaches 185 F, the thermo switch is supposed to complete the circuit, grounding the igniton wire, and then the fans will come on.

Hoping you understood that mess, I will explain my idea. If you run a switch after the relay on the circuit that comes from ignition, you can manually complete, or break, that circuit. You will be bypassing the thermo switch and the switch inside the car will take its place.

Now, the terminals on the relay are as follows.

#1 is the farthest to the front and the passenger side of the vehicle. This terminal is the "output" of the switch on the relay and this wire goes to the fan motor.
#2 is the farthest to the interior and the passenger side of the vehicle. This is the "output" of the coil part of the relay (ignition circuit). This wire normally runs to the thermo swich but this is the wire you will run to your switch.
#3 is the closest to the engine and the front of the car. This has power coming from the battery for the fan motor.
#4 is the closest to the engine and the interior of the car. This comes from the igniton.
#3&1 are on the same circuit and #4&2 are on the same circuit.

To summerize this mess. Take the wire at relay terminal #2, run it to a switch, and then to ground. Hope this helps and sorry if its confusing, its hard to explain over the internet.