Heater matrix acting more efficient than my rad?

[merlin2002]

well ive got an fc swithch and it makes the fans come on at exactly 93 deg and turns them off at 87 deg it does it everytime at these temps checked many times on the commander. im guessing yours is faulty or you are taking measurements from a dif place to the standard temp sensor.
 
also i didnt think you can make changes to fan settings on the commander i thought it had to be dont on pc connected to the ecu???

Did you replace the lower of the 2 thermo switches?

[cyman]

i did it ages ago i would have to go and take a look. all i can remember is its on the back of the water filler housing.

[PDale]

Lots of mis-info here guys. The thermoswitch does NOT turn the fans on. With stock ECU, fans do not come on until temp reaches 105C. The thermoswitch creates an extra ground when it switches on and increases the fan speed but only when the fans are turned on by your ECU or you turn the A/C on.

FC thermoswitch will just mean the fan speed with be on a higher setting earlier than if you kept the stock FD thermoswitch. But this is still pretty pointless as the fans are not being turned on by the stock ECU until 105C anyway. If you get a Power FC, your tuner can set the temp the fans come on, it can\'t be done on the commander, only using the datalogit software. This info is all in the FSM (except Power FC haha). I\'ll find out the page numbers later so you can check it out.

[merlin2002]

Lots of mis-info here guys. The thermoswitch does NOT turn the fans on. With stock ECU, fans do not come on until temp reaches 105C. The thermoswitch creates an extra ground when it switches on and increases the fan speed but only when the fans are turned on by your ECU or you turn the A/C on.

FC thermoswitch will just mean the fan speed with be on a higher setting earlier than if you kept the stock FD thermoswitch. But this is still pretty pointless as the fans are not being turned on by the stock ECU until 105C anyway. If you get a Power FC, your tuner can set the temp the fans come on, it can\'t be done on the commander, only using the datalogit software. This info is all in the FSM (except Power FC haha). I\'ll find out the page numbers later so you can check it out.

This was my understanding also! I also just read about the data logit!

Anyone got this equipment on here?

[DJ Tommo]

^^^^^^
Ah someone who knows his stuff Useful and interesting info to know! Thanks PDale!

Cheers

Tom

[philiwily]

I have one but your a bit far away, quite a few guys on here have dataloggit\'s so im sure you could meet up with someone.

[cyman]

Lots of mis-info here guys. The thermoswitch does NOT turn the fans on. With stock ECU, fans do not come on until temp reaches 105C. The thermoswitch creates an extra ground when it switches on and increases the fan speed but only when the fans are turned on by your ECU or you turn the A/C on.
 
FC thermoswitch will just mean the fan speed with be on a higher setting earlier than if you kept the stock FD thermoswitch. But this is still pretty pointless as the fans are not being turned on by the stock ECU until 105C anyway. If you get a Power FC, your tuner can set the temp the fans come on, it can\'t be done on the commander, only using the datalogit software. This info is all in the FSM (except Power FC haha). I\'ll find out the page numbers later so you can check it out.

sorry pdale but you are wrong here close to the right conclusion but still wrong   . either the ecu or the thermoswitch or the ac will turn fans on at first speed. then if 2 of them are on its the 2nd speed if all 3 are on then they come on at the highest speed. so the thermoswitch does turn the fans on on its own.
 
see below it was taken from rx7club there are loads of threads on there about it this was just the easiest to find
 
Cooling fan operation 101:
The fan system has three speeds in which the speed selection depends upon the engine’s demand for cooling. There are three elements that demand the fans to operate: ECM, AC, and Water Temperature Thermoswitch. Also there was a Mazda recall that added a fan off delay circuit to resolve an underhood temperature problem but we won’t go into that here…
 
The fans have three separate motor winding taps whereas as voltage is applied via relays to consecutive (in any order) taps the fan speed increases.
The fans can be turned to LOW speed by any ONE of the ECM, AC or Thermoswitch actuating the respective relay(s). Relays 2 and 4 are operated by the ECM, relay 1 by the AC and relay 3 by the water thermoswitch. The ECM uses two relays for fault tolerance (they are redundant).
The fans can be turned to MEDIUM speed by any TWO of the ECM, AC or Thermoswitch closing the appropriate relays.
The fans can be turned to HIGH speed by all THREE (ECM, AC, and Thermoswitch) closing all of the relays.
 
it explains it more clearly i took ages reading up on this before i did it. trust me it works anyone can feel free to come and see my car if they require proof.

[cyman]

also merlin the lower of the two sensors is your thermoswitch so thats the one to that should of been swapped

[DJ Tommo]

Also there was a Mazda recall that added a fan off delay circuit to resolve an underhood temperature problem but we won’t go into that here…

This is an issue i have and didnt know about the recall. Is it still possible to get it done?

Cheers

Tom

[merlin2002]

also merlin the lower of the two sensors is your thermoswitch so thats the one to that should of been swapped

Thats the one I swapped out.... with that sensor unplgged the fans speed is at half speed with it pluged in is at full speed....as long as fans are actually on! as that sensor goes to relay 3

[PDale]

sorry pdale but you are wrong here close to the right conclusion but still wrong   . either the ecu or the thermoswitch or the ac will turn fans on at first speed. then if 2 of them are on its the 2nd speed if all 3 are on then they come on at the highest speed. so the thermoswitch does turn the fans on on its own.
 
see below it was taken from rx7club there are loads of threads on there about it this was just the easiest to find
 
Cooling fan operation 101:
The fan system has three speeds in which the speed selection depends upon the engine’s demand for cooling. There are three elements that demand the fans to operate: ECM, AC, and Water Temperature Thermoswitch. Also there was a Mazda recall that added a fan off delay circuit to resolve an underhood temperature problem but we won’t go into that here…
 
The fans have three separate motor winding taps whereas as voltage is applied via relays to consecutive (in any order) taps the fan speed increases.
The fans can be turned to LOW speed by any ONE of the ECM, AC or Thermoswitch actuating the respective relay(s). Relays 2 and 4 are operated by the ECM, relay 1 by the AC and relay 3 by the water thermoswitch. The ECM uses two relays for fault tolerance (they are redundant).
The fans can be turned to MEDIUM speed by any TWO of the ECM, AC or Thermoswitch closing the appropriate relays.
The fans can be turned to HIGH speed by all THREE (ECM, AC, and Thermoswitch) closing all of the relays.
 
it explains it more clearly i took ages reading up on this before i did it. trust me it works anyone can feel free to come and see my car if they require proof.

I too have read numerous posts on RX7Club as I was trying to resolve a fan problem a while ago. There are posts that support my findings on there too. I know my car doesn\'t have the fan control module recall so can\'t comment if someones car does.

Based on a car not having the fan control module recall, using the FSM and myself running electrical diagnostics on my car, I believe I am correct in saying the thermoswitch  has no influence on turning the fans on. During my diagnostics I used test leads direct from my battery to the fan cable that corresponds to the thermoswitch circuit. I found it only acted as a ground, so required power from at least either the air con circuit(Relay No.1) or the ECU circuit(Relay No.2 and No.4). This is supported by the FSM wiring diagram Pg Z-40 (1994 wiring diagram, excluding fan control module recall).

As I say, I do not have any experience with the fan control module as my car does not have it. So in this instance we are probably both right.

[cyman]

mate i have an fc thermoswitch fitted the thermoswitch WILL turn the fans on on its own with neither the ecu requesting it or the ac switch being on. i have it that is what happens.

[PDale]

well ive got an fc swithch and it makes the fans come on at exactly 93 deg and turns them off at 87 deg it does it everytime at these temps checked many times on the commander. im guessing yours is faulty or you are taking measurements from a dif place to the standard temp sensor.
 
also i didnt think you can make changes to fan settings on the commander i thought it had to be dont on pc connected to the ecu???

mate i have an fc thermoswitch fitted the thermoswitch WILL turn the  fans on on its own with neither the ecu requesting it or the ac switch  being on. i have it that is what happens.

Sorry dude but you are wrong. You said yourself your fans come on at 93C, which would be your Power FC telling your fans to come on. The FC thermoswitch switches on at 97C which would just increase the fan speed to medium if your temps got that high. Your Power FC is turning the fans on! You could have a thermoswitch that switches on at 80C, it still wouldn\'t turn the fans on!

[cyman]

unfortunatley for me i have a 1992 jdm rex and the only wiring diagram i have is for the 1994 lhd car usa and canada i believe and i would like to say its the same but ive tried to use it for some other faults i had and its soooo bloody different to mine  

[cyman]

nope pfc is set higher than that. its the switch because i did back to back tests when i fitted it to make sure it was worth doing
 
sorry dude proof of the pudding and all that