Manual Cooling fan switch install...help.

GOing to hook in the switch to control my fan manually.

I cut the #14 wire and put it in there, Right? Where's this wire? is it on that little box behind the pass. headlight? How do I tell which wire it is?

I cut the #14 wire and put it in there, Right? Where's this wire? is it on that little box behind the pass. headlight?

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Yes #14 wire, and Yes it's located where you said.

How do I tell which wire it is?

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The wiring harness connecter is numbered where it attaches to the relay module.

David

High speed winding?

What's this about a High speed winding in there? Should I switch that one? WHat harm will result if I just unplug the fan temp switch? will the motor get a rich condition?

E-mail me at dkneibert@charter.net for a wiring diagram and instructions that XR7Dave gave me a couple years ago. It shows how to wire both or either fan for manual or automatic operation.

This diagram was updated last year to shut the low speed windings off while the high speed fan was running. I never got around to rewiring mine because I thought it was working good enough already.

David

Dave, I sent you an e-mail, Thanks.

So you can set it to come on automatically? Can you pick what temp? What's Normal oper range, 180-200 degrees?

Here's another one: I pulled out the fan sensor switch to put in an aftermarket guage right into that fitting that I think goes into the heater core hose. I left the fan switch plugged into the harness to avoid a Check engine light and just laid it along the side of the charger. I thought about it and am wondering if that switch also tells the Computer what temp the engine is and adjusts the fuel accordingly. other than gas mileage, what's that down side of doing this.

I had plumbed them both into a "T" fitting but was getting an unaccurate reading. Anyone got any ideas for plumbing them both in? Is there any other area the I can put the aftermarket probe into to get a temp reading? Pictures would be cool!

There are two coolant temp sensors, the one near the DIS is for the EEC and provides all data necessary to turn fans on and off, adjust timing and fuel for hot or cold conditions and several other things. Don't mess with it.

The sensor/sender near the water pump provides info for your coolant temp gauge.

The diagram and instructions I e-mailed you this morning keep all the standard sensors and EEC settings and functions. For example the low speed fan will still come on when you turn the AC or Defrosters on.

You can manually override the stock settings to turn the fans on earlier, but if you screw up, and set them too high the standard settings will still work.

Generally the fan settings are about 10 degrees higher than the thermostat you selected. For example 180 degree stat would start the low speed fan at 190 and the high at 200. I like mine to run as cool as possible and have the fans set to start at 180 and 190. It's important to start the fan in low speed (too many amps to start in high), that's why the high speed is set to start 10 degrees higher.

David

Temp guage

So where's a good place to plumb in an aftermarket temp guage?

Dave - that's an interesting question about staging the fans. I still have the old MN12 "cool fan switch" with a 200deg sensor on the back of the rad. ,which is sliced into the relay wire & grounded. I also have a switch on the ground wire, so I can return to nornal/stock settings in the winter months. Splicing into just one relay wire like that would it still stage the fan speeds correctly?
Jim.

Jim,

If the wire you are splicing into is the #14 then yes, because that controls the low speed fan. However if the temp still goes high enough to activate the high speed fan it will drag the high speed fan down a little by still having the low speed on at the same time.

If your controlling the high speed fan by grounding wire # (can't recall) then it will shorten the fan life or possibly blow the fuseable link because of pulling too many amps starting the fan in high speed.

David

David - that's very interesting. Because the old MN12 Performance "cool fan switch" splices into the # 17 (LG/P) wire, which according to your info., is the high speed. That would explain why just a few months after installing the "CFS" in my 94 I fried the fan and totally melted the 60amp fuse in the main fuse box. I couldn't find an aftermarket fan at the time and ended up buying the whole fan & shroud from Ford at $350; plus an auto electrican bypassed the fuse (part of the box was fried too) and put in a heavy duty fuseable link. I've had no problems since, but I do see the voltmeter take a dive when it kicks on. Fortunately my 93 has the same set-up , but earlier models already use a fuseable link for the fan; so I guess it's safe. Would you therefore recommend changing my set-up over to the #14 (low speed) for safety. I did see one message on the forum some time ago where a member had spliced into both wires with a 2 pole switch; so he could turn either one on according to temp.
What do you think?
Thanks, Jim.

Is this bad for the motor? I hotwired my fan this way....

Unplugged the fan and ran some 12 gauge wire from the plug directly to the battery through a inline fuse (30amps) and then to a switch which i mounted under the climate control. When on it is high speed. Only bad thing i know of is that it can be turned on even though the ignition is off and drain the battery. But it was very easy to do and a friend who is good with car electrics and I did it in about an hour.

Jim,

I would suggest getting a second controller & relay then wiring it like this diagram that David Dalke drew.

http://members.tccoa.com/dneibert/fan relays.jpg

Starting the fan in high is rough on it and the wiring as you have already discovered. You can't just switch from wire #17 to #14 because #17 is grounded to start the fan and #14 is ungrounded or cut to start the fan.

David

Thanks Dave - I might in the meantime use the switch & wiring I have, to just put the switch in line with #14 and see how it works out manually. My current set-up runs from the splice on #17 to a switch on the console and back to the ground for the pass. headlight. So I can just take it off the ground, cut #14 and use both wires to put the switch in series.
Jim.