HOW TO: Control an electric fan with a factory thermoswitch
08-16-10, 08:45 AM
#52
I used the S5 diagram to wire up a nissan quest fan, so far its not turning on, but there could be a few reasons for this...
The fan is 2 speed and i pulled both the ran relays from the car at the yard. they are identical 4 pin (Nissan 25230) units. Problem is, unlike most otehr relays I've seen, there are no markings on the bottom of the relay identify which pin corresponds to which function. In liew of actuall markings I hooked the relay up, assuming that the position of the function in the diagram corresponded to the location of the pin underneath....probably wrong but its all I got. I've got a 5 pin relay from a Taurus efan that i could try, but I wanted to be consistent if possible.
Also, instead of the stock switch, I found an S5 style (normaly open) switch that comes on @193 and off @ 185. The probe is about 1 cm shorter than the stock sensor. While this will likely have some affect on the reading do you think it could keep it from activating at all?
I only plan on using one speed for now, so I have a fused 12V power line going to one (don't know if its high or low...) power wire from the fan. The other is crimped and wrapped. Could this cause a problem?
The fan is 2 speed and i pulled both the ran relays from the car at the yard. they are identical 4 pin (Nissan 25230) units. Problem is, unlike most otehr relays I've seen, there are no markings on the bottom of the relay identify which pin corresponds to which function. In liew of actuall markings I hooked the relay up, assuming that the position of the function in the diagram corresponded to the location of the pin underneath....probably wrong but its all I got. I've got a 5 pin relay from a Taurus efan that i could try, but I wanted to be consistent if possible.
Also, instead of the stock switch, I found an S5 style (normaly open) switch that comes on @193 and off @ 185. The probe is about 1 cm shorter than the stock sensor. While this will likely have some affect on the reading do you think it could keep it from activating at all?
I only plan on using one speed for now, so I have a fused 12V power line going to one (don't know if its high or low...) power wire from the fan. The other is crimped and wrapped. Could this cause a problem?
08-17-10, 08:56 AM
#53
Problem Solved.
While I wasn't able to find a pinout for that Nissan relay I was able to find out it was only rated for 20 amps...
I guess the stock (nissan) setup must have run them in parallel?
So I swaped in the beefier Ford Taurus relay (thats actually labeled) and bam! Fan comes on at 198* and shuts off @ 185* (according to my Rtek). I guess the thermosensor is still accurate afterall. The switch I'm using is from an 80's subaru, its the same thread pitch as stock, but unlike the S4 switch its normally open, and comes on at 194* [I attribute turn-on of 198 to the fact that the subaru sensor is 1cm shorter than stock so it doesn't see as much coolant flow]
Now I just need to decide if I want high speed on a switch in the cabin, or rig up another temp switch....
While I wasn't able to find a pinout for that Nissan relay I was able to find out it was only rated for 20 amps...
I guess the stock (nissan) setup must have run them in parallel? So I swaped in the beefier Ford Taurus relay (thats actually labeled) and bam! Fan comes on at 198* and shuts off @ 185* (according to my Rtek). I guess the thermosensor is still accurate afterall. The switch I'm using is from an 80's subaru, its the same thread pitch as stock, but unlike the S4 switch its normally open, and comes on at 194* [I attribute turn-on of 198 to the fact that the subaru sensor is 1cm shorter than stock so it doesn't see as much coolant flow]
Now I just need to decide if I want high speed on a switch in the cabin, or rig up another temp switch....
08-17-10, 05:38 PM
#54
Nice write-up. Definitely archive-worthy!!
I'm curious where the best place to locate the thermoswitch is. I'm running out of places as I've got my aftermarket temp gauge sensor/sender on the front of the waterpump housing.
I need to do some research before making any changes, but can I use the signal coming off the OEM thermosensor for both the OEM and aftermarket gauges? For that matter can I disable the OEM gauge as it's redundant. Is the S5 thermosensor for the gauge the one located on the rear iron or the back of the waterpump housing? Sorry for the noobish questions, just stuff off the top of my head.
Just thought of this, I saw some people doing it...if everyone who used a thermoswitch from another car listed it and the temp it switches at would be helpful. I'd prefer to have something lower than the S5 207 but as easy to wire up. I don't really want to go S4 and need the extra wiring.
I'm curious where the best place to locate the thermoswitch is. I'm running out of places as I've got my aftermarket temp gauge sensor/sender on the front of the waterpump housing.
I need to do some research before making any changes, but can I use the signal coming off the OEM thermosensor for both the OEM and aftermarket gauges? For that matter can I disable the OEM gauge as it's redundant. Is the S5 thermosensor for the gauge the one located on the rear iron or the back of the waterpump housing? Sorry for the noobish questions, just stuff off the top of my head.
Just thought of this, I saw some people doing it...if everyone who used a thermoswitch from another car listed it and the temp it switches at would be helpful. I'd prefer to have something lower than the S5 207 but as easy to wire up. I don't really want to go S4 and need the extra wiring.
08-17-10, 09:57 PM
#55
Ok....
I'm curious where the best place to locate the thermoswitch is. I'm running out of places as I've got my aftermarket temp gauge sensor/sender on the front of the waterpump housing.
I need to do some research before making any changes, but can I use the signal coming off the OEM thermosensor for both the OEM and aftermarket gauges? For that matter can I disable the OEM gauge as it's redundant. Is the S5 thermosensor for the gauge the one located on the rear iron or the back of the waterpump housing? Sorry for the noobish questions, just stuff off the top of my head.
Just thought of this, I saw some people doing it...if everyone who used a thermoswitch from another car listed it and the temp it switches at would be helpful. I'd prefer to have something lower than the S5 207 but as easy to wire up. I don't really want to go S4 and need the extra wiring.
I need to do some research before making any changes, but can I use the signal coming off the OEM thermosensor for both the OEM and aftermarket gauges? For that matter can I disable the OEM gauge as it's redundant. Is the S5 thermosensor for the gauge the one located on the rear iron or the back of the waterpump housing? Sorry for the noobish questions, just stuff off the top of my head.
Just thought of this, I saw some people doing it...if everyone who used a thermoswitch from another car listed it and the temp it switches at would be helpful. I'd prefer to have something lower than the S5 207 but as easy to wire up. I don't really want to go S4 and need the extra wiring.
It's highly unlikely that the stock sensor will be properly scaled to work with any aftermarket gauge. However there might be some aftermarket gauges whose sensor probe is the same thread as the stock sensor and could replace it. I think* the prosport coolant temp sensors are the same size as stock.
As far as the thermoswitch location (for an efan) any place near the thermostat is fine, this includes the upper radiator hose or even in the rad itself. Actually you could really put it anywhere IF you have an adjustable switch.
As far as replacement swtiches, there are are a handful, I spend a day researching switches. Avoid the ***-backwards S4 style switch. I will look for the list I made and post later...
08-17-10, 11:01 PM
#56
A thermoswitch with s5 style wiring would be preferable for the simplicity, and I think a lot of people would prefer their fans to come on between 190 and 200F. For those of you with the factory tapped thermostat housing, you would want to find a thermoswitch that will screw in to the factory M16x1.5 thread. Otherwise if you are drilling and tapping something I would go with a thermoswitch that is NPT.
Using the factory s4 switch is a bit of a cheap bastard mod and there are legitimate gripes about it. Yet I still think that using the factory s4 switch is preferable to wiring the fan straight to ignition power, relying only on a manual switch, or using a poorly functioning radiator probe (push-in style).
Using the factory s4 switch is a bit of a cheap bastard mod and there are legitimate gripes about it. Yet I still think that using the factory s4 switch is preferable to wiring the fan straight to ignition power, relying only on a manual switch, or using a poorly functioning radiator probe (push-in style).
08-17-10, 11:53 PM
#57
First, there are three stock sensors 1) the thermo sensor on the back of the wp housing - this feeds the ecu. 2) the temp gauge sensor located on rear driver side of the block - this feeds the stock temp gauge 3) the thermo switch located in the thermostat cover - this provides the signal for the optional e-fan in front of the a/c condenser.
It's highly unlikely that the stock sensor will be properly scaled to work with any aftermarket gauge. However there might be some aftermarket gauges whose sensor probe is the same thread as the stock sensor and could replace it. I think* the prosport coolant temp sensors are the same size as stock.
As far as the thermoswitch location (for an efan) any place near the thermostat is fine, this includes the upper radiator hose or even in the rad itself. Actually you could really put it anywhere IF you have an adjustable switch.
As far as replacement swtiches, there are are a handful, I spend a day researching switches. Avoid the ***-backwards S4 style switch. I will look for the list I made and post later...
It's highly unlikely that the stock sensor will be properly scaled to work with any aftermarket gauge. However there might be some aftermarket gauges whose sensor probe is the same thread as the stock sensor and could replace it. I think* the prosport coolant temp sensors are the same size as stock.
As far as the thermoswitch location (for an efan) any place near the thermostat is fine, this includes the upper radiator hose or even in the rad itself. Actually you could really put it anywhere IF you have an adjustable switch.
As far as replacement swtiches, there are are a handful, I spend a day researching switches. Avoid the ***-backwards S4 style switch. I will look for the list I made and post later...
I've got prosport temp gauges and my engine is in pieces being rebuilt. Next time I pull the parts out I'll try and screw the prosport sender into the rear iron. That would be a nifty way to reduce wiring in the engine compartment. Though a friend suggested keeping both OEM and aftermarket gauges for security. Either way I've got time to decide.
I've also got a S4 Koyo rad out of the car. It has a threaded spot on the bottom driver side. The sensor would not come in contact with coolant, because of that would it be accurate to put a thermo switch there?
About the thermo switch temps. Friend I talked to offered some advice about not setting or getting a temp that is near the thermostat temp. His electric fan was set somewhere near the thermostat so the thermostat was working overtime when the temps would drop and it would close, then reopen, then close. His thermostat had a short lifespan. He had to move the efan switch to a temp up so the two weren't fighting against each other.
08-18-10, 01:27 AM
#58
S5 thermostat covers don't have a thermo switch. We got the cheap plastic covers that crack. Ours also don't have a radiator cap.
I've got prosport temp gauges and my engine is in pieces being rebuilt. Next time I pull the parts out I'll try and screw the prosport sender into the rear iron. That would be a nifty way to reduce wiring in the engine compartment. Though a friend suggested keeping both OEM and aftermarket gauges for security. Either way I've got time to decide.
I've also got a S4 Koyo rad out of the car. It has a threaded spot on the bottom driver side. The sensor would not come in contact with coolant, because of that would it be accurate to put a thermo switch there?
About the thermo switch temps. Friend I talked to offered some advice about not setting or getting a temp that is near the thermostat temp. His electric fan was set somewhere near the thermostat so the thermostat was working overtime when threw temps would drop and it would close, then reopen, then close. His thermostat had a short lifespan. He had to move the efan switch to a temp up so the two weren't fighting against each other.
I've got prosport temp gauges and my engine is in pieces being rebuilt. Next time I pull the parts out I'll try and screw the prosport sender into the rear iron. That would be a nifty way to reduce wiring in the engine compartment. Though a friend suggested keeping both OEM and aftermarket gauges for security. Either way I've got time to decide.
I've also got a S4 Koyo rad out of the car. It has a threaded spot on the bottom driver side. The sensor would not come in contact with coolant, because of that would it be accurate to put a thermo switch there?
About the thermo switch temps. Friend I talked to offered some advice about not setting or getting a temp that is near the thermostat temp. His electric fan was set somewhere near the thermostat so the thermostat was working overtime when threw temps would drop and it would close, then reopen, then close. His thermostat had a short lifespan. He had to move the efan switch to a temp up so the two weren't fighting against each other.
Apparently that huge sensor (same size as the vw switch from clokker's writeup IIRC) in the bottom of the read is from some accelerated warmup or emissions related crap. On aftermarket rads (or at least koyos) that sensor does not see coolant. The location could be drilled to allow it to see coolant flow however.
I have no plans of retaining the stock temp gauge sensor, what can itr do that a properly installed quality aftermarket gauge cannot? Id rather bypass thee hassle of having to pull and trap the wp housing over having a useless gauge.
Your friend is right, if the fan shut off temp is too low it will attempt to cool the car past the point where the thermostat kicks in, it will run all the time trying to get a car designed to run@ 185* to run@ 180*. --defeating the major benefit of an efan in the first place. This can be especially problematic on the interstate if the fan is set lower than the cruising temp as a running fan is a sizable obstruction to cooling at speed.
08-18-10, 02:15 AM
#59
I suppose I could try and find an adapter for the drain plug in the bottom of the radiator?
08-18-10, 07:42 AM
#60
Was also my thought but the thermostat housing is a different bolt pattern. I believe Mazdatrix sells an aluminum S5 neck, but it would still need to be tapped for the thermoswitch.
I suppose I could try and find an adapter for the drain plug in the bottom of the radiator?
I suppose I could try and find an adapter for the drain plug in the bottom of the radiator?
I think the spot you are referring to is on the bottom of the rad on the Driver Side. The stock sender is a 3/8" pipe thread ...
I had my temp gauge sensor there for a while. The downside is that you are measuring the coolant AFTER passing through the radiator. This makes for interesting info, but is in no way a good indicator of the engine coolant temp. Also, since the coolant is already passing the rad, this might make a poor place for the fan switch. OTOH, with the adjustable switch, maybe it's a great place?
I had my temp gauge sensor there for a while. The downside is that you are measuring the coolant AFTER passing through the radiator. This makes for interesting info, but is in no way a good indicator of the engine coolant temp. Also, since the coolant is already passing the rad, this might make a poor place for the fan switch. OTOH, with the adjustable switch, maybe it's a great place?
So, I have been playing around (What?!!!) with my efan setup. I installed a VDO temp sensor in the Bottom of my Radiator in the OEM spot. I have been watching the RETURN coolant temps, trying to determine the right temp setting on my adjustable fan thermostat. My goal is to determine the correct temp setting by monitoring the coolant after the heat rejection occurs in the radiator. This has been going on for a couple of weeks now.
I believe that the following is true:
A.) If the fan temp is set above the initial coolant thermostat opening, ie. 185* and
B.) the return temp stays below the initial thermostat opening temp, then
C.) I have sufficient cooling without
D.) excessive e-fan running. (excessive alternator/fuel consumption)
The temp controller measures the coolant at the top hose to the radiator. Fan is always temp controlled on *low* speed.
If I set the fan to run on low continuously, the return coolant temp will hover in the 160* range all the time. This is city driving, parked etc. It slowly rises up to about 185* on the highway, 55-60 mph and stays.
If I set the fan temp controller to 215*, the return temps get very erratic. The temps range from 185* to 250*. Yes, I said 250*. Evans Coolant, Baby! The temp is obviously overshooting. The highway temps will hover around 195*.
If I set the temp controller to 195*, the return runs from 170-185*. No overshooting, no overcooling etc.
This testing was done with day temps in the 80* range as we have had over the last couple of weeks here in the Dallas area.
I believe that the following is true:
A.) If the fan temp is set above the initial coolant thermostat opening, ie. 185* and
B.) the return temp stays below the initial thermostat opening temp, then
C.) I have sufficient cooling without
D.) excessive e-fan running. (excessive alternator/fuel consumption)
The temp controller measures the coolant at the top hose to the radiator. Fan is always temp controlled on *low* speed.
If I set the fan to run on low continuously, the return coolant temp will hover in the 160* range all the time. This is city driving, parked etc. It slowly rises up to about 185* on the highway, 55-60 mph and stays.
If I set the fan temp controller to 215*, the return temps get very erratic. The temps range from 185* to 250*. Yes, I said 250*. Evans Coolant, Baby! The temp is obviously overshooting. The highway temps will hover around 195*.
If I set the temp controller to 195*, the return runs from 170-185*. No overshooting, no overcooling etc.
This testing was done with day temps in the 80* range as we have had over the last couple of weeks here in the Dallas area.
08-18-10, 07:54 AM
#61
Was also my thought but the thermostat housing is a different bolt pattern. I believe Mazdatrix sells an aluminum S5 neck, but it would still need to be tapped for the thermoswitch.
I suppose I could try and find an adapter for the drain plug in the bottom of the radiator?
I suppose I could try and find an adapter for the drain plug in the bottom of the radiator?
I am not a fan of adapters, they typically push the element too far out of the flow of whatever they are supposed to be measuring. Then fan switch I'm using is only 1 cm shorter than the stock one and it comes on 4* later than it should (cuts off right at 185 though).
Edit: Apparently I've read one too many efan threads lately and can't remember who said what lol, lots of good info in that Taurus fan thread. Thanks jackchild.
08-18-10, 02:31 PM
#65
Not really worth it imo, i blocked off the cap since I got s5 rad.
*that was a new waterpump a year ago, i should of painted it b4 i put it on lol
Would be a good place to install a 3/8npt probe but i already did my efan setup b4 that.
08-20-10, 04:17 PM
#67
From what I recall, a Taurus 2-speed e-fan (on low) seems to be a bit much for a FD alt to run. My battery's not in the greatest of shape (ran dead a few times, but holds a charge just fine), but the FD alt I had was doing a great job till the e-fan came along. So after a few days of being pushed, the FD alt was pulled, brackets were fabbed and the upgrade was made to the 130 amp Taurus alt before the FD one conked out (pulled from the exact same junkyard car as the fan lol). Not sure what the current draw was from the e-fan, but the Taurus alt does the job exceptionally well. Car is a bone stock s4 GXL with manual trans conversion and only an aftermarket head unit.
08-22-10, 12:26 PM
#71
Thought I might chime in too.
This is actually the setup I used for a Grand Cherokee two speed fan in my 4x4 Explorer. It works perfectly. The diodes are necessary to keep the a/c from turning on when don't want it to. Probably could delete the ground relay, but I thought it prudent.
This setup allows me to turn off the fan when I need to even if the thermoswitch is on. In my 4x4 I need this when I traverse creeks and other wet obstacles. Then the high speed comes on with a/c or a flip of the switch. It would be somewhat easy to add two thermoswitches of different trip points so if you start to over heat the high speed with kick in automatically.
I would also like to mention that if you want your fan to stay on for a few minutes after you turn off the car, then you can use capacitors in line with the relay trigger +12v. When the 12v is switched on it charges the capacitors. When it's turned off, they discharge keeping your fan on until they are drained. The larger the capacitor, the longer the fan will stay on.
This is actually the setup I used for a Grand Cherokee two speed fan in my 4x4 Explorer. It works perfectly. The diodes are necessary to keep the a/c from turning on when don't want it to. Probably could delete the ground relay, but I thought it prudent.
This setup allows me to turn off the fan when I need to even if the thermoswitch is on. In my 4x4 I need this when I traverse creeks and other wet obstacles. Then the high speed comes on with a/c or a flip of the switch. It would be somewhat easy to add two thermoswitches of different trip points so if you start to over heat the high speed with kick in automatically.
I would also like to mention that if you want your fan to stay on for a few minutes after you turn off the car, then you can use capacitors in line with the relay trigger +12v. When the 12v is switched on it charges the capacitors. When it's turned off, they discharge keeping your fan on until they are drained. The larger the capacitor, the longer the fan will stay on.
08-23-10, 12:49 PM
#73
Yikes! I"m sure its not as complicated as it looks, but still...
This is exactly what I was looking for I even get to keep the 3 position switch from my maual setup! Low speed will keep my temps where they need to be running continuously in the summer, but when winter rolls around it might actually be able to take a break, lol. Once I find a temp switch that works, and get the A/C working I'll have to rewire the fan.
This is exactly what I was looking for I even get to keep the 3 position switch from my maual setup! Low speed will keep my temps where they need to be running continuously in the summer, but when winter rolls around it might actually be able to take a break, lol. Once I find a temp switch that works, and get the A/C working I'll have to rewire the fan.
09-23-10, 02:38 AM
#74
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The +12V ignition power for the relay can come from the green diagnostic connector if you are s4. As for the fan power itself... I'm really reluctant to recommend a particular factory ignition-switched circuit for that. Electric fans pull a lot of current. I'm concerned there would be problems if you didn't use a relay and pull it right from the battery.