I got tired of replacing stuff on my 85SE and having the fan STILL not work, so built a control that allows me to mechanically adjust the temp at which the radiator fan comes ON and also allow me to have the fan always ON if I want.
I mounted the box in the front trunk close to the fan relay near the driver's side headlight
[This message has been edited by PaulJK (edited 07-15-2007).]
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05:29 AM
PFF
System Bot
PaulJK Member
Posts: 6638 From: Los Angeles Registered: Oct 2001
The slotted post coming out of the right side of the project box is from the Fan controller - it's on the other side of the Fan controller shown in the pic. The temp probe goes out a hole in the back of the project box and to the nearby radiator; there is more than enough wire on the temp probe to do this.
I got the engraved plate from a local guy that does nice work but charges too much ($30 - ouch)
[This message has been edited by PaulJK (edited 07-15-2007).]
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05:35 AM
PaulJK Member
Posts: 6638 From: Los Angeles Registered: Oct 2001
Notice from the diagram that the coolant temp switch (bottom left) has two wires - green with black stripe and green with white stripe. Also notice that the switch grounds on the bottom. So, if you ground either of these green wires, you act like the switch and cause the fan relay to turn the radiator fan ON. I chose the green with black stripe because I didn't want to give anything in the A/C system a reason not to work .
I simply soldered a wire to the Green wire with the black stripe (at the fan relay) and ran it into my project box. I then soldered (2) leads to it - (1) going to a terminal on the rocker switch and (1) going to a terminal on the Fan controller. I ran the remaining terminal on the switch and the remaining terminal on the Fan controller to ground. This puts them in a parallel circuit.
This project ignores the stock coolant temp switch but leaves it in the circuit. If you want to eliminate the stock temp. switch, just cut the green wire (instead of tapping off of it) and use the side connected to the fan relay. When I close the rocker switch, everything is by-passed, ground is supplied which trips the fan relay and the fan comes ON. The temp probe will still heat up and supply a ground, but the fan will already be ON.
If the rocker is OFF, the temp probe attached to the radiator heats up and eventually sends a ground to the fan controller in the box which supplies a ground to the relay and it turns the fan ON. The slotted post coming out of the project box is from the Fan controller and allows the temp at which the fan comes ON to be set.
Simple but effective. Hope this helps
[This message has been edited by PaulJK (edited 07-15-2007).]
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05:51 AM
kyote Member
Posts: 1232 From: Germantown, Wisconsin - Metro Milwaukee Area Registered: Sep 2001
The probe mounts on the radiator. Here's the instructions:
Now that I think about it, I wish I could add something to keep the fan running for a few minutes after the engine is turned off. That would keep the coolant temp from going up everytime the engine is turned off .
[This message has been edited by PaulJK (edited 07-16-2007).]
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04:49 AM
kyote Member
Posts: 1232 From: Germantown, Wisconsin - Metro Milwaukee Area Registered: Sep 2001
The constant 12+ might be a way to go. I'll have to study the wiring diagram a little more. i was trying not to modify too much of the wiring and would prefer to "add-in" a timer or something that could simply be removed if it didn't work.
As far as a cabin mount, there was not a good place for it in my car. I'm not sure if the wiring on the temp. probe would stretch that far and it's hard-wired, so you can't splice it.
[This message has been edited by PaulJK (edited 07-16-2007).]
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09:51 PM
Jul 19th, 2007
PaulJK Member
Posts: 6638 From: Los Angeles Registered: Oct 2001
I wasn't keen on the idea of pushing that plastic hold-down through, but carefully and slowly it went through .
I pulled the car out of the garage and turned the adjusting post on the controller to the middle of its position. Started the car and watched the temp guage. When it climbed to 205, the fan still had not started, so I slowly turned the controller post counter-clockwise until the fan started. Done . I'll check it again later, but it should now be set pretty close to turning the fan on at 205 - 210 .
[This message has been edited by PaulJK (edited 07-19-2007).]
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09:31 PM
Jul 20th, 2007
Joe Torma Member
Posts: 3485 From: Hillsborough, NJ USA Registered: Jul 2001
can we be a little more clear about this? I seriously want to undergo this process as my next project! but I can't quite follow what's going on... New to the electical work and it's my first car/fiero. Anyone want to write up a tutorial with pictures?
Notice from the diagram that the coolant temp switch (bottom left) has two wires - green with black stripe and green with white stripe. Also notice that the switch grounds on the bottom. So, if you ground either of these green wires, you act like the switch and cause the fan relay to turn the radiator fan ON...
I simply soldered a wire to the Green wire with the black stripe (at the fan relay) and ran it into my project box. I then soldered (2) leads to it - (1) going to a terminal on the rocker switch and (1) going to a terminal on the Fan controller. I ran the remaining terminal on the switch and the remaining terminal on the Fan controller to ground. This puts them in a parallel circuit.
Great idea and execution of the fan controller. Quick question for clarity...
I am familiar with diagrams and have been doing wiring (self-taught) for about 20 years. Car stereos, alarms, troubleshooting, even wired in a few 220v air compressors and water heaters. I'm no EE, but I can usually hold my own. The above 2 statements seem to contradict each other. I see in the diagram how the Coolant Temp Switch (let's call it CTS so it's easier to type ) has 2 wires coming from it. What I don't see are the 2 leads soldered to the green/black wire.
In the diagram it appears that the green/black wire is attached to one switch on the CTS and controls one fan speed while the green/white is attached to another switch in the CTS and controls another fan speed. Am I reading that wrong? Where in the diagram are the 2 leads to the green/black wire?
[This message has been edited by Chad87FB (edited 08-11-2007).]
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02:57 AM
PaulJK Member
Posts: 6638 From: Los Angeles Registered: Oct 2001
Green Arrow: Fan Relay mounted as shown in the pic [1st post, 2nd pic]
Red Arrow: Green wire with Black trace as described
Purple Arrow: Green wire with white trace as described
NOTE: If you are looking at the relay in the headlight area, you will see these wires as described or something that should be reasonably close depending on what year car you have. If you are looking inside the passenger compartment / dash area, BE CAREFUL. I recently discovered that there is a green wire with white stripe coming out of the dimmer switch that carries power for the dash lights ! So be careful which green wire with white stripe you tap into.
My fan is only a single speed which is either ON or OFF, so i can't advise in regards to the 2 speed fan.
My comment above in regards to getting help was meant to be well-intentioned, not sarcastic. With somethings, you should NOT strike off on your own - fiero wiring being a BIG one .I'd LOVE to be able to replace my own brakes, but refuse to do it until I have someone there to watch and check what i'm doing.
[This message has been edited by PaulJK (edited 08-11-2007).]
I believe I can do this now. Few questions first! Bonzo suggested we ground the green/white. But can we also use green/black? In addition, how do we dissemble the headlight to get to these wires?
I got it to work, thanks a bunch, now my fan won't Piss me off. Just need an idea on where to mount this rocker switch. Any ideas? By the way, how do we get the light to work on the switch?
For the ones that don't know green and white stripe is the ground for the fan. If you have a two speed fan it is for the low speed. The green, and black stripe is ground for the high speed part of the fan. I am gonna do this one to my car. Good job Dude, and thanks for shareing it with us all.
I got it to work, thanks a bunch, now my fan won't Piss me off. Just need an idea on where to mount this rocker switch. Any ideas? By the way, how do we get the light to work on the switch?
I put my switch just below the rear hatch release:
The slotted post coming out of the right side of the project box is from the Fan controller - it's on the other side of the Fan controller shown in the pic. The temp probe goes out a hole in the back of the project box and to the nearby radiator; there is more than enough wire on the temp probe to do this.
I got the engraved plate from a local guy that does nice work but charges too much ($30 - ouch)
How do you wire to illuminate it? Mine has a ground, illumination, and power (plus symbol)... thanks
i just installed an LT1 twin cooling fan setup on my 86 grand prix. i bought a variable speed control which is made by flex a lite from jegs. it has a probe that goes between the fins of the radiator.the controller runs the fans for a short time after the engine is turned off. when they first come on they run at 60%, then after a 10* temp rise they go to 100%. it is also adjustable from around 160* to 220* , also have a switch to manually turn them on. so far works great.
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08:32 PM
PaulJK Member
Posts: 6638 From: Los Angeles Registered: Oct 2001
To illuminate the switch ? - i couldn't figure it out so I gave up - I figured i'd never see it in the trunk anyway
jerry - sounds like a really nice set-up. After doing this mod, i can't imagine even trying to mess with fixing a stock system where the fans isn't coming on - this is a faster AND cheaper thing to do .
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11:05 PM
Sep 17th, 2007
madcurl Member
Posts: 21401 From: In a Van down by the Kern River Registered: Jul 2003
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