Manual Engine Cooling Fan Switch Install

NorthrnSCownr

Registered User
Im going to install a two speed toggle switch to manually run the cooling fan. Looking for tips/suggestions esp. for where you may have run the wires, and put the ground.
I'll run 2 wires from the fan switch,(the low and high) keeping the ground intact as it is working, then grounding the two speed toggle as close as possible to the switch on the lower dash area. Where have any of you done this?
 
Personally, I wouldn't run the power for the fan through the swith, use the switch to activate relays under the hood. And make sure to use in-line fuses as well. The relays will be able to handle he power for the fans much better than a switch and will reduce the risk of an electrical fire under your dash from the swithc melting.
 
Personally, I wouldn't run the power for the fan through the swith, use the switch to activate relays under the hood. And make sure to use in-line fuses as well. The relays will be able to handle he power for the fans much better than a switch and will reduce the risk of an electrical fire under your dash from the swithc melting.
Has anyone done this that can give a bit more info on procedure please? I'd like to get this done before my trip out of state next week. Thanks,
Tom
 
Tom - if you search the forum there are plenty of previous discussions on this subject. You have the relays/controlers like the ones from 'flex-a-lite', but you DEFINITELY don't want to use toggle switches in line with the existing wiring. Way too much amperage. An easy, less complex solution is to remove the IRCM relay box from behind the passenger headlight (in front of the air filter) cut line #14 and splice the tail from the relay box end onto #17, that breaks the ground on the low speed fan and makes it run continuously (if you put spade connectors on both ends you can cancel that in the winter by just connecting it back up again). The reason for splicing it onto #17 (which is the high speed fan) is that should your coolant temp. climb high enough to bring the faster fan winding on it will automatically cut off the low speed; as you don't want both energized at the same time. During the summer the low speed comes on with a/c use but goes off again once you reach highway speed (about 47mph). That's why you suddenly see the temp. guage rise even though you are cruising along. Disconnecting it in the winter restores the stock settings and reduces the battery draw at start-up, otherwise that fan runs as soon as the ignition is on. Additionally you can put one of those adjustable stats on the high speed wiring, by splicing on another wire to #17 and running it to ground thru an adj. stat. On mine I simply have a 200 deg. sensor on the radiator and that grounds/brings on the high speed. However, I've found with the low speed running all the time my high speed hardly comes on.
I learnt the hard way by just having the sensor on the high speed and that current draw alone fried my fuse box. Now the low speed to high speed change-over is far less demanding on the circuit. Strangely enough my '93 has a fuseable link on the fan wiring and I've never had any problems, yet it fried my '94 which was fused thru the under hood box. Now of course I use a separate fuseable link for the '94 as a safeguard.
Hope that's not too confusing,
JIm.
 
This is XR7 Dave's cooling modification, that I stole long time ago, so thank him for it! I have!! Good Luck!

Calvin
 
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Thanks for the diagram. I have found this in searches, but honestly, my lack of experience steered me to try for a more verbal direction. I see the list of parts needed, and I see it is an easy job, but I am unsure of where to place these items under the hood....

-Parts required, 2 ea. 30 amp automotive relays, 2 ea. thermostatic fan controller, 1 ea. 1 amp diode and 1 ea. 3amp in line fuse. All this stuff can be purchased from Autozone or Advanced. The controllers are generic and are most commonly used when converting a belt driven fan to electric.

The wires numbered on the diagram are labeled on the harness of the integrated relay control module located in front of the air box.-
Any more help/pictures is/are appreciated...
Thanks,
Tom
 
Tom - take the easy route first and splice # 14 wire onto #17 on the IRCM relay box and see how it works out for you. Cost you 1/2 hour and a couple of bucks for the connectors. If you buy the 3M type that allows spade connectors to plug right in to the slice, it makes it very easy to connect back up your #14 wire in winter.
If you are not happy with that the 'flex-a-lite' or the above relay set-up with adjustable stats is more complex to install, but very adjustable and still relatively cheap. Those Bosch 30amp relays are only a couple of bucks each. Finally if you go the chip route ( I currently don't know anyone that will burn you a chip for just changing fan settings) then whatever you decide on the temp. settings you are stuck with. Finally there is the EEC tuner which is the ultimate tool for changing anything on your computer, but very expensive if you have a relatively stock motor and only want to change your fan settings.
If you still want to risk your toggle switches, atleast use a relay for the switch and take you fan power (fused) directly off a battery source.
Good Luck, Jim.
 
Thanks Jim

The first couple options sound good to me.
I really dont need more than the low speed. I drove 400 miles last weekend twice, even hitting traffic on the highway, and didn't get above the center of norm. BUT i dont want to push it either. I just want a simple solution. Where have you seen those 3m spade connectors? That sounds good to me. Thanks,
Tom
 
Tom - I think I got mine at PepBoys. They are the small cable size splice; but instead of slicing in the added wire, you use a spade connector and plug it in. Just makes life easier when you may want to disable it (Some guys reported back that with the low fan on at ignition, they had some starting problems in very cold weather).
Good Luck,
Jim.
 
I had my car wired using the diagram Calvin posted for about a year with no problems....however it's got a flaw. It doesn't turn off the low speed windings when high speed is running and causes the fan to turn a little slower than it should.

This newer diagram uses two relays for that reason.



fan%20relays.jpg



David
 
Thanks for the help. I just ended up splicing into the low speed and sending it to lighted toggle in the car. (fusable linked of course) works like a champ. Its great, the toggle is just left and below the hood release latch, so I can kick it on with my feet even :D and the glowing blue light tells me when its engaged. I think all SC's should be so equiped:)
 
Sounds good, but just a word of caution, because the typical illuminated toggle switch is only rated for 15 amps. Even though you have a fusible link or an in-line fuse I would guess the low speed fan motor pulls more than that.
Jim.
 
You could have just wired the switch to open and close the circut on wire #14, and since it just triggers the relay, none of the heavy amp stuff is required.

David
 
Dave, with the reading I was doing here, and all the different approaches to solving this problum, I figured I would go with the way I did, for two reasons. 1) I had a time window to resolve the issue 2) My electrical knowlege/experience prior to this task = 0 :p
I would like for you to elaborate a bit more about how that works, though.
Regards, Tom
 
Tom,

Breaking the circut on wire #14 turns the fan on. It can be done with relays as the diagram shows or by installing a rocker or toggle switch. Doing it that way retains all the normal EEC controlled fan functions, such as automatcially coming on with the AC until you reach 45 mph.

For high speed fan operation wire #17 is grounded. Again this can be done by placing a wire tap on wire #17 and attaching the wire to a switch and the other wire from the switch to ground.

Low speed should always be started first to avoid pulling too many amps and burning out the fan motor or the fuseable link.
The diagram just uses a pair of relays and automatic controllers to do the same thing. I agree with Jim about the danger of running that many amps through the switch, so you might want to rewire to the #14 instead and just use a low amp 12 volt power source from under the dash for the light in the rocker switch.

Once you do it, you'll see it's pretty easy.

David
 
Tom,

From the radio/CD player, there is a small plastic covered junction box under the dash on my car that contains the power wire connections. Since your only using that power to light the switch it doesn't need a fuse.

David
 
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