Fan Therm Switch
#1
Fan Therm Switch
Pulling the motor and the wire to the fan thermo switch on the back of the water pump housing broke. It broke right at the connector, so no room to repair. I can probably source another connector with some wire from another harness, but do I need this with the adaptronic. Since the ECU is controlling the fan, is the sensor in the water pump housing still used?
#2
Rotary Freak
iTrader: (10)
Forgive me if I’m misunderstanding your question, but do you realize you’re talking about an INPUT vs an OUTPUT?
the ECU reads the water temperature from the sensor on the back of the water pump housing. Unless this is an automatic car which had an additional sensor back there for something else.
The ECU is driving an OUTPUT to switch on your fan, but will not know the temperature with the broken sensor connection .
There is a single-wire sensor on the side of the keg (next to the oil pressure sender) which drives the temp gauge on the cluster; maybe this is why you’re confused and didn’t realize the ECU has no idea what your water temp is right now.
I’m not trying to insult your intelligence, just clarifying since many many people confuse the several thermo”switch” for thermo”sensor”.
the ECU reads the water temperature from the sensor on the back of the water pump housing. Unless this is an automatic car which had an additional sensor back there for something else.
The ECU is driving an OUTPUT to switch on your fan, but will not know the temperature with the broken sensor connection .
There is a single-wire sensor on the side of the keg (next to the oil pressure sender) which drives the temp gauge on the cluster; maybe this is why you’re confused and didn’t realize the ECU has no idea what your water temp is right now.
I’m not trying to insult your intelligence, just clarifying since many many people confuse the several thermo”switch” for thermo”sensor”.
Last edited by DC5Daniel; 03-07-22 at 11:59 AM.
#3
No insult taken. I am happy for any feedback. The image below will show the sensor I am looking at. My understanding is that the green sensor is the actual temp sensor and the black one being pointed at is a switch for the fans. If I am incorrect, please correct me. The black connector is the one that has the single wire and is broken right at the connector.
#4
10000 RPM Lane
iTrader: (2)
don’t make me use that ugly S word again
- Fan thermoswitch. This is the coolant temp sensor on the back of the water pump housing under the ECU coolant sensor. It has a one wire connector. This is one of the fan speed inputs. The factory switch operates at 107 deg. Celsius.
- The ECU. The factory ECU can read the engine's coolant temps from the coolant temp sensor on the back of the water pump housing (the 2-wire sensor with a green plug on the back of the water pump housing). It uses this input as another fan speed input.
https://www.rx7club.com/3rd-generati.../#post10026311
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- Fan thermoswitch. This is the coolant temp sensor on the back of the water pump housing under the ECU coolant sensor. It has a one wire connector. This is one of the fan speed inputs. The factory switch operates at 107 deg. Celsius.
- The ECU. The factory ECU can read the engine's coolant temps from the coolant temp sensor on the back of the water pump housing (the 2-wire sensor with a green plug on the back of the water pump housing). It uses this input as another fan speed input.
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#5
www.lms-efi.com
iTrader: (27)
The switch runs to the X14 connector. When I build harnesses, I generally use an output from the ECU to replace the fan switch and run it to the X14. So you don’t need the switch but you’ll need to connect an output from the ECU. Bonus of doing this is that you can turn the fan on at a lower, more reasonable temperature.
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