Electric Fan Shutting Off

Jarvis said:

Definitely a 3G. The fan is a Flex-a-lite. Look like this
http://www.summitracing.com/parts/flx-175/overview/make/ford

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ok... that fan has an controller on the top of it that adjusts with the turn of the knob. That is the good news. The bad news is those fans are terrible and are notorious for the controller breaking, and the fan itself is not very good. Go to the FAL website or google and you will find the install instructions which will show you the proper wiring, What you need to do is install a a good fuse holder( large blade type 10g wire not the cheap little blade fuse with 14g wire) with at least a 30 amp fuse for the power wire to the battery side of the solenoid.



Make sure the ground is also attached to a solid ground point. Also, there should be a triangle shaped connector on the A/C power wire that feeds the controller. It turns on the fan whenever the A/C is on. You want to adjust the fan so it comes on about 5-10 degrees warmer than your stat.

I have a similar fan, my controller box is set up a little differently. I'm getting rid of it though, mine never came on thermostatically as it should and flipping a switch constantly would have annoyed me.

If you don't have a high current alternator, you can forget about using an electric fan. The stock 65 amp alternator on 86-93 Mustangs isn't big enough to run the fan and the rest of the car. If you have a 94 or later Mustang, the stock 3g alternator should be fine if it is working correctly.

Switching a fan on and off manually is a bad idea. Too many guys have been distracted (hot girl kissing on their neck, too much to drink, dog tired and not thinking clearly) and cooked things because they forgot to flip the switch. An equal number have forgotten to turn the switch off for the same reasons and run down their battery.

The best fan controller available today is a DC Control unit. www.dccontrol.com. Cost is about $???. Be prepared to wait 4 weeks or more to receive your controller once you have sent in your payment. The controllers are custom made in small lots and lead times can stretch out.

Next best is a SPAL controller - $70-$120 See http://www.spalusa.com/store/Main.aspx?html=pwmv3. eBay will have the controllers for a bargain price: do a Google search and see what you find.

At the bottom are the Hayden or Imperial controllers available through Advance Discount Auto Parts and AutoZone. The non adjustable one is about $30 ( Hayden 226206) and the adjustable one is about $60 (Hayden 226204). I recommend you do a Google search on Hayden and the part number for more info.

Do not use a simple on/off switch without using a relay. The current load can burn up the typical cheap automotive switch very quickly. The fan draws 30+amps and you need to use #10 wire on the fan power and ground wiring.

If you are good with electrical stuff (90% of the people here aren't), build your own controller. The numbers on the diagram (#86, #87, etc) refer to the numbers on the bottom of a typical automotive relay.



Note that the temp sensor in the diagram needs to match the thermostat in your engine. The preferred arrangement is to have it open about 5 degrees above the thermostat.

To allow the ignition switch to control the fan so that it does not run when the ignition is off, connect the relay contact #86 to the red/green wire on the ignition coil or to the red/yellow wire on the coolant level sensor.

If you are an experienced electronics tech or electrical engineer, email me and I will send you the prototype drawings of a fan controller that is similar in function to the DC Control unit. It is a build it, troubleshoot it yourself item. I will not build or troubleshoot units, so it is not suitable for anyone who isn't really good with electronics.
See my post at http://www.stangnet.com/mustang-for...-sooo-much-amperage-help.859590/#post-8645840 to get the drawings and full details.

Alternate placement for a temp gauge sender or temp switch/temp sensor for an electric fan. Use the heater feed that comes off the intake manifold. Cut the rubber hose that connects the manifold water feed to the heater and splice in a tee adapter for the temp gauge sender. Be sure to use the same water feed line as the ECT sensor. That way you will get the most accurate temp readings.

Tee adapter info:
Make a pilgrimage to your local hardware or home supply center and get some copper pipe and a tee that fits the temp gauge sender. Solder two pieces of copper pipe onto a copper pipe tee with threads in the tee part. Find the correct brass fitting to match the temp sender threads to the tee fitting.

jrichker, the OP said he has a 3g alt so he should be good there. To the OP, sounds like the controller for the fan crapped out like I said they are prone to, and the prior owner just hard wired it into the fusebox? Can you post a picture of the fan and the wiring coming off it.

That attempt to tap the fuse is nasty looking. I wouldn't do that unless I wanted to burn someone's car up.

Jarvis said:

Their is one black and one red wire. The red wire goes across the bay into a little whole that goes into the drivers compartment and is wired in behind a 25amp fuse in the AC slot. Black goes to somewhere on the frame. When the fan stopped i just jiggled it iin the fusebox and it kicked on and got the temps down.

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As mentioned, that wiring is a fire waiting to happen. Like I thought, the controller on that fan is broken and the prior owner just hard wired the fan to the fuse box . You now have a few options

1. leave it as is and hope your car doesn't overheat from the fan failing or worse burn up the wiring and car
2. correct the wiring and install a controller and keep the BM fan
3. correct the wiring, install a controller, and replace the fan with a better e fan

IMO you should at least do option 2 which has been detailed earlier in this post. You can do option 3 with a jy Taurus fan and a new controller for under $200.