Electrical Running relays and the contour fan

Waz900

Member
Apr 22, 2005
13
2
13
Sewell, New Jersey
Hey guys,

This topic has been covered a lot in many different ways, but I didn’t see a concrete model that matches mine and I would also like feedback from people who know more than me, so I wanted to ask for insight on my “design.” I’m wiring my contour fans to a Derale PWM controller. I mapped everything out in my diagram, and I want to see if anyone sees any fault in the logic. Where I’m mostly concerned is the fan (+) post on bottom right of the controller. With the way I have this set up, my intention is for the fan positive to only be energized when the relays have key-on power. Is there anything I’m missing in this plan? I’ve been reading extensively on how to wire this properly, and I guess I’m just looking for other opinions if this looks feasible and safe. I’ve probably gotten in my own head with the amount I’ve read on this topic, but I’d like to know it’s sound thinking for my own peace of mind. Thanks in advance for your help.

Adam
 

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KRUISR

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Apr 16, 2015
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I am not sure of the details of the Derale controller specs as far as amperage capabilities so I can't comment on that part.

The Contour fans use a 70A relay from the factory to turn on each speed. I wired my Contour fans as shown below and still use both speeds, though high speed never comes on.

Contour Fans Schematic.jpg

You could replace the fan switch shown in my diagram with almost any fan controller or fan switch and be good as well.

So basically my fans are hot all the time with no issues. On occasion when I turn off the engine and the fans are running as I do so, they will continue to run for 10-30 seconds and then turn off. My fan switch on temp is 195 degrees so I basically need full normal engine operating temperature to start the fans. My fan switch is located in the lower rad hose as well, in my opinion the best location (discharge side of rad before the water pump). This way your fans will cool the coolant based on coolant temperature, not engine temperature.

Another question, are you planning to run fans on low speed or high speed?
 
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91GTstroked

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Jun 14, 2007
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I am not sure of the details of the Derale controller specs as far as amperage capabilities so I can't comment on that part.

The Contour fans use a 70A relay from the factory to turn on each speed. I wired my Contour fans as shown below and still use both speeds, though high speed never comes on.

Contour Fans Schematic.jpg

You could replace the fan switch shown in my diagram with almost any fan controller or fan switch and be good as well.

So basically my fans are hot all the time with no issues. On occasion when I turn off the engine and the fans are running as I do so, they will continue to run for 10-30 seconds and then turn off. My fan switch on temp is 195 degrees so I basically need full normal engine operating temperature to start the fans. My fan switch is located in the lower rad hose as well, in my opinion the best location (discharge side of rad before the water pump). This way your fans will cool the coolant based on coolant temperature, not engine temperature.

Another question, are you planning to run fans on low speed or high speed?
This is some good info. Like the op, I've been considering the contour fans, but with a dakota digital controller.

Any pictures you can share with us?
 

KRUISR

Well-Known Member
Apr 16, 2015
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Details my build. Just did a near identical install on my '04 F150 using an OEM Contour fuse box/relay box and wiring (including adding the thermoresistor to get dual speed on a '10 F150 fan unit - works great).

On my F150 I connected the A/C circuit as well using this diagram.

Contour Fans Schematic with AC.jpg

I also added the toggles like I did on my Mustang. If you want any specific pics, let me know and I can get them in the next couple days.
 

Blown88GT

Founding Member
Nov 13, 1999
2,154
512
164
Palm Beach Gardens, FL
Hey guys,

This topic has been covered a lot in many different ways, but I didn’t see a concrete model that matches mine and I would also like feedback from people who know more than me, so I wanted to ask for insight on my “design.” I’m wiring my contour fans to a Derale PWM controller. I mapped everything out in my diagram, and I want to see if anyone sees any fault in the logic. Where I’m mostly concerned is the fan (+) post on bottom right of the controller. With the way I have this set up, my intention is for the fan positive to only be energized when the relays have key-on power. Is there anything I’m missing in this plan? I’ve been reading extensively on how to wire this properly, and I guess I’m just looking for other opinions if this looks feasible and safe. I’ve probably gotten in my own head with the amount I’ve read on this topic, but I’d like to know it’s sound thinking for my own peace of mind. Thanks in advance for your help.

Adam
Your design won't work. The Derale Fan (+) is an output which you can't control with a relay attached to it, One (not 2) relay would have to be connected to the Derale Battery (+).
The relay is not necessary at all, connect the Battery(+) with a fuselink directly to the battery.

BTW, the Derale PWM controller is a "clone" of the DC Control (DCC) PWM controller. DCC owns the patent & licenses the design to Derale.
Brian (Mr. DCC) & I are both electrical engineers & have one of the first two pre-production FK-35's.

How to properly wire the DCC is on his website.

You might need the input filter which allows running the low-impedance Ford dual fans
 

Waz900

Member
Apr 22, 2005
13
2
13
Sewell, New Jersey
Your design won't work. The Derale Fan (+) is an output which you can't control with a relay attached to it, One (not 2) relay would have to be connected to the Derale Battery (+).
The relay is not necessary at all, connect the Battery(+) with a fuselink directly to the battery.

BTW, the Derale PWM controller is a "clone" of the DC Control (DCC) PWM controller. DCC owns the patent & licenses the design to Derale.
Brian (Mr. DCC) & I are both electrical engineers & have one of the first two pre-production FK-35's.

How to properly wire the DCC is on his website.

You might need the input filter which allows running the low-impedance Ford dual fans
Thank you for the feedback. My reasoning behind the relays were so that it would not run when the car is off. My goal was to have the fans run through the relays that are triggered by key-on power. I'm concerned with the fans draining the battery when the car is not in use. If I did not connect a relay at all, as you suggested, wouldn't I run into this problem?
 

Waz900

Member
Apr 22, 2005
13
2
13
Sewell, New Jersey
I am not sure of the details of the Derale controller specs as far as amperage capabilities so I can't comment on that part.

The Contour fans use a 70A relay from the factory to turn on each speed. I wired my Contour fans as shown below and still use both speeds, though high speed never comes on.

Contour Fans Schematic.jpg

You could replace the fan switch shown in my diagram with almost any fan controller or fan switch and be good as well.

So basically my fans are hot all the time with no issues. On occasion when I turn off the engine and the fans are running as I do so, they will continue to run for 10-30 seconds and then turn off. My fan switch on temp is 195 degrees so I basically need full normal engine operating temperature to start the fans. My fan switch is located in the lower rad hose as well, in my opinion the best location (discharge side of rad before the water pump). This way your fans will cool the coolant based on coolant temperature, not engine temperature.

Another question, are you planning to run fans on low speed or high speed?
Thanks for your reply. I was not aware that the Contour fans ran through 70A relays from the factory. I'm at work now, but I want to take a look at the information that you posted and all of the pictures. I'll follow up if I have any questions.
 

Blown88GT

Founding Member
Nov 13, 1999
2,154
512
164
Palm Beach Gardens, FL
Thank you for the feedback. 1. My reasoning behind the relays were so that it would not run when the car is off. 2. My goal was to have the fans run through the relays that are triggered by key-on power. 3. I'm concerned with the fans draining the battery when the car is not in use. 4. If I did not connect a relay at all, as you suggested, wouldn't I run into this problem?
1 I'm sorry, your reasoning is flawed.
2. It is not going to work your way, no matter how hard you wish it to.
3. They won't run at all unless the temp probe sees the radiator temp at the set temp.
4. No. I have mine connected exactly as I described. It's only worked for 20 years with the Mark VIII fan & now the dual Contour fans.

What do you find wrong with the Derale instructions in the attachment below?
 

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Steel1

Mustang Master
Aug 18, 2017
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Connecticut
I run dual Intrepid fans with a Flexalite controller, when I shut the car off at operating temp
the fans will run for 10-15 seconds then shut off. No battery draining issues.
I'm guessing it's fairly common scenario in relation to fan controllers ?
 

KRUISR

Well-Known Member
Apr 16, 2015
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Don't worry about fan relays being hot at all times. That is how the Contour/Mystique/Cougar (and likely all those Mondeo's across the pond) is factory wired. I have never heard of a fan stuck on issue with those cars. I have owned 3 of these cars totaling over 750,000 km of use with never a failure of the cooling fan system. Your control system can still be operated via key on power, but don't worry about hot relays failing, just get the right ones.

My diagrams above show the factory Contour wire gauge, fuse and relay sizes. Match that and I would expect no issues.