Mark VIII Fan Schematic
Safety Car
Joined: Mar 2005
Posts: 3,503
Likes: 2
From: Raleigh NC
Looks like a double pole relay needs to be used. Or they were limited in the current carrying capacity on their board, so they used two contacts or something?
The fan connects to: "If you have a later car (91 or newer), there is an integrated controller module (ICM) (12B577 basic #). This is located in the engine compartment. It is a black metal box about 8"X6"X1.5". It runs the cooling fan, the fuel pump, and the EEC power.
Also called the Relay Control Module (RCM).
40amp fuse.
Here are the setpoints for the fan (a 2-speed) for the a/c:
If high side pressure is <150psi, RPM of motor = 1000
As pressure increases up, the Control increases RPM
At 295psi, fan speed is 1800 RPM
If high side reaches 425psi, AC compressor stops, but fan still runs
at 200 psi, compressor is allowed to operate.
The fan is turned off at speed > 47 MPH.
Fan turns back on when speed drops to about 42MPH
The fan connects to: "If you have a later car (91 or newer), there is an integrated controller module (ICM) (12B577 basic #). This is located in the engine compartment. It is a black metal box about 8"X6"X1.5". It runs the cooling fan, the fuel pump, and the EEC power.
Also called the Relay Control Module (RCM).
40amp fuse.
Here are the setpoints for the fan (a 2-speed) for the a/c:
If high side pressure is <150psi, RPM of motor = 1000
As pressure increases up, the Control increases RPM
At 295psi, fan speed is 1800 RPM
If high side reaches 425psi, AC compressor stops, but fan still runs
at 200 psi, compressor is allowed to operate.
The fan is turned off at speed > 47 MPH.
Fan turns back on when speed drops to about 42MPH
Last edited by PhotoVette1; Jul 31, 2006 at 11:44 AM.
Thread Starter
Melting Slicks
Joined: Oct 2004
Posts: 2,662
Likes: 8
From: Knoxville Tennessee
From what you describe, this fan needs a variable control module to increase the speed as the need dictates. That a 40 amp relay is what is needed to control it. I still don't understand the lower amps for this fan.
Bernie
Bernie
Safety Car
Joined: May 2005
Posts: 4,176
Likes: 7
From: Jennings LA
I was looking in our shop manuals at work today and it looks like they were variable speed from '93 on, I will try to dig up an older book and see if they were ever operated as a 2 speed fan. and what the purpose of the third wire in the conector was for.
Thread Starter
Melting Slicks
Joined: Oct 2004
Posts: 2,662
Likes: 8
From: Knoxville Tennessee
Gator,
I appreciate all the help you can give us on this. I keep hearing that the alt. should spike 100 amps on start up and run continous at 40 amps. My fan off a '93 spikes 30 amps and runs continously at 8 amps hooked to our Snap-on electrical machine. I am trying to make sure I am getting full rpms from the fan and also how to install it correctly. The blue wire is positive, the outside black wire is negative and the center wire doesn't do anything. Thanks again for your help!
Bernie
I appreciate all the help you can give us on this. I keep hearing that the alt. should spike 100 amps on start up and run continous at 40 amps. My fan off a '93 spikes 30 amps and runs continously at 8 amps hooked to our Snap-on electrical machine. I am trying to make sure I am getting full rpms from the fan and also how to install it correctly. The blue wire is positive, the outside black wire is negative and the center wire doesn't do anything. Thanks again for your help!
Bernie
Safety Car
Joined: Mar 2005
Posts: 3,503
Likes: 2
From: Raleigh NC
Originally Posted by BerniesVette
Gator,
I appreciate all the help you can give us on this. I keep hearing that the alt. should spike 100 amps on start up and run continous at 40 amps. My fan off a '93 spikes 30 amps and runs continously at 8 amps hooked to our Snap-on electrical machine. I am trying to make sure I am getting full rpms from the fan and also how to install it correctly. The blue wire is positive, the outside black wire is negative and the center wire doesn't do anything. Thanks again for your help!
Bernie
I appreciate all the help you can give us on this. I keep hearing that the alt. should spike 100 amps on start up and run continous at 40 amps. My fan off a '93 spikes 30 amps and runs continously at 8 amps hooked to our Snap-on electrical machine. I am trying to make sure I am getting full rpms from the fan and also how to install it correctly. The blue wire is positive, the outside black wire is negative and the center wire doesn't do anything. Thanks again for your help!
Bernie
Thread Starter
Melting Slicks
Joined: Oct 2004
Posts: 2,662
Likes: 8
From: Knoxville Tennessee
PhotoVette,
I saw this fan come out of a '93 lincoln with the V8 still in the car. I might be getting full rpm but I am confused with the readings I am getting. Gator may be able to shed some light on this mystery for me!
Bernie
I saw this fan come out of a '93 lincoln with the V8 still in the car. I might be getting full rpm but I am confused with the readings I am getting. Gator may be able to shed some light on this mystery for me!
Bernie
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Safety Car
Joined: May 2005
Posts: 4,176
Likes: 7
From: Jennings LA
news from the other side
I checked today the Mark VIII fan was allways a variable speed fan, why the extra wire in the harness unused? only ford knows why. It was probably designed differently then changed after the wire harness was in production. I also talked to a ford engineer today and he said it should never spike at 100 amps that would smoke the controller. it has been a few years but he recalls it should spike 30 amps 40 at most on start up and run at around 8 to 10 amps. you should be able to run this with an aftermarket controller with no problem. hope this helps
Thread Starter
Melting Slicks
Joined: Oct 2004
Posts: 2,662
Likes: 8
From: Knoxville Tennessee
Gator,
Thanks for the info we needed to make sure our fans are performing the way they should and to know what we need to buy to install them! This is why the forum is such a great place for those of us that make modifications the old fashioned way; trial and error and mostly error!
Now I can start putting together a parts list to finish this project.
Bernie
Thanks for the info we needed to make sure our fans are performing the way they should and to know what we need to buy to install them! This is why the forum is such a great place for those of us that make modifications the old fashioned way; trial and error and mostly error!
Now I can start putting together a parts list to finish this project.
Bernie
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Looks like it's setup to run two relays into the single blue wire. I guess you could have two temp sensors, and have one turn on at one temp, and the other relay energize at a higher temperature. I gotta figure out how I'm going to wire this beastie.
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Today's update:
My fan has these two part numbers stamped on the shroud:
F3LE-8C607-AD (near the top)
F3LE-8146-AC (near the bottom)
The date code block has places for 92, 93, 94 and 95.
I hooked it to my Jeep via jumper cables, with the following results:
black ground and blue positive: full speed
black ground and black positive: full speed
black ground and both positives: full speed
Now I'm really confused as to the reason for the extra wire.
My fan has these two part numbers stamped on the shroud:
F3LE-8C607-AD (near the top)
F3LE-8146-AC (near the bottom)
The date code block has places for 92, 93, 94 and 95.
I hooked it to my Jeep via jumper cables, with the following results:
black ground and blue positive: full speed
black ground and black positive: full speed
black ground and both positives: full speed
Now I'm really confused as to the reason for the extra wire.
Thread Starter
Melting Slicks
Joined: Oct 2004
Posts: 2,662
Likes: 8
From: Knoxville Tennessee
Since you are getting full speed with the black neg. and blue pos. I would just use them and either use a regular thermo switch or the delta controller to activate it. It just depends on whether you want full speed when on or variable speed.
Bernie
Bernie