New Foxbody Owner With A Fan Question

[m3x1c0]

Hey all! Just traded a couple cars for an 88 notchback. The car is pretty much setup for track use. It is a 306 (I think) with a custom turbo added to it. I cant remember the trim on that turbo but its pretty bitchin. Its a very custom application so I'm learning a lot about it right now. (tuning is done on a laptop, the rear has discs, AC and power steering deleted, turbo plumbing is all custom) I do have one issue keeping me from driving that I need some help with.

My issue is that the cars radiator fan stopped working. The PO drove to my house over an hour from where he is from so the fan was working great up until right after I took ownership of course. It appears to be a taurus fan hooked up to a couple relays and switched by the factory temperature sensor. I was trying to see if the fan was borked so I rigged up a 30a switch directly to the solenoid terminal to the high speed wire of the fan. It smoked once out of the switch but the fan worked for a bit so I closed the hood and drove to the store. by the time I got to the store the fan had gone out. I'm pretty sure I should have put the switch between the ground off the fan and not between the power (and should have used a fuse.)

Does anyone know how to make a switchable turn on for this fan using the existing relays? couldnt I just ground the wire going to the temp switch to turn the fan on? (I have no idea how temp switches work.) Im going to get another fan after work but dont want to burn it out if the problem was my ghetto rigged wiring.

As you can tell I'm quite a noob when it comes to electrical. My other car is a grand national that I rebuilt the motor and did some wiring on but all under the supervision of someone smarter than me.

looking forward to learning!

 

[TOOLOW91]

Get yourself a heavy duty fan controller. Those fans draw major amperage on start up. Try to find a fan controller with a soft start feature to lighten the load on start up. Some guys like the flex a lite controllers. Some like De rales. Another great one is DCC but he builds to order and takes a bit to get it to you.

 

[m3x1c0]

Get yourself a heavy duty fan controller. Those fans draw major amperage on start up. Try to find a fan controller with a soft start feature to lighten the load on start up. Some guys like the flex a lite controllers. Some like De rales. Another great one is DCC but he builds to order and takes a bit to get it to you.

I may do that since I like the idea of using a toggle for racing. However, my goal now is just to get the car working. I'd like to use the relays it currently has, they are in some sort of custom harness that appears to maybe go to the ECM as well. I'll post a pic later and maybe that will help. Just need to get the car functional so I can assess the tune and other things that may need to be done.

As far as I can remember there are two relays one for each of the fan speeds. A white wire off the temp switch appears to go to one of the relays. I see a black wire going all the way around the engine compartment to a harness on the passenger side that goes through firewall, cant remember which which relay it goes to but I'm assuming its for low speed and maybe controlled by ecm. There is a third relay in this grouping but cant remember what it went to (im at work and the car is at home.) I tested all three relays by hooking to the battery and couldn't hear a click out of any of them. How likely is it that 3 relays are all burnt up after working perfectly fine less than an hour ago?

 

[TOOLOW91]

I may do that since I like the idea of using a toggle for racing. However, my goal now is just to get the car working. I'd like to use the relays it currently has, they are in some sort of custom harness that appears to maybe go to the ECM as well. I'll post a pic later and maybe that will help. Just need to get the car functional so I can assess the tune and other things that may need to be done.

As far as I can remember there are two relays one for each of the fan speeds. A white wire off the temp switch appears to go to one of the relays. I see a black wire going all the way around the engine compartment to a harness on the passenger side that goes through firewall, cant remember which which relay it goes to but I'm assuming its for low speed and maybe controlled by ecm. There is a third relay in this grouping but cant remember what it went to (im at work and the car is at home.) I tested all three relays by hooking to the battery and couldn't hear a click out of any of them. How likely is it that 3 relays are all burnt up after working perfectly fine less than an hour ago?

You may have had a major spike and cooked the coil in the relay . To wire it on a switch your gonna need to just use one speed and keep it simple . Those things can spike 90 amps on start up so you would need relays heavy enough to handle that in line with each other and the wiring to reflect that as well. Still not ideal but will work.
30 is hot from battery with appropriate fuse in line.
85 is ground
86 is power to the coil on the relay this is the switch lead to the relay . other side of the switch will go to a 12v source to control the relay when the switch is activated .
87 is the lead from the relay to the fan .

 

[m3x1c0]

You may have had a major spike and cooked the coil in the relay . To wire it on a switch your gonna need to just use one speed and keep it simple . Those things can spike 90 amps on start up so you would need relays heavy enough to handle that in line with each other and the wiring to reflect that as well. Still not ideal but will work.
30 is hot from battery with appropriate fuse in line.
85 is ground
86 is power to the coil on the relay this is the switch lead to the relay . other side of the switch will go to a 12v source to control the relay when the switch is activated .
87 is the lead from the relay to the fan .

What is a good source for 12v near the front driver side of the car?

 

[m3x1c0]

Also if the current wiring is hooked up appropriately how could I bypass the temp sensor and switch the relays on? 12v to the temp send wire?

 

[TOOLOW91]

Also if the current wiring is hooked up appropriately how could I bypass the temp sensor and switch the relays on? 12v to the temp send wire?

The way I just wrote it you would not be using any temp sensor . It would rely solely on the switch . This is why I'm saying it's easier just to get a good controller for it . @jrichker could maybe she'd some more light on this too


Sent from my iPhone using my fingers while my auto correct makes me seem illiterate

 

[jrichker]

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. Welcome to Delta Current Control. 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.

 

[m3x1c0]

Thank you for the info. I have studied your diagrams and looking at the current setup in the car: mine is very similarly setup. I will post more details after I finish creating a diagram for it.

One question: I have confirmed that the fan itself is burnt out. I went to the salvage yard and every single 3.8 car had the fan robbed out of it (damn it internet.) I went ahead and pulled a similar fan out of a 4 cylinder car. It appears to have the exact same mounting pattern for the fan. I figure I can just replace the motors but I cannot get the stupid plastic fan off of my old fans motor setup. The fan is stuck to the shaft of the motor somehow. There is a clip that came off easily but I cant see any other way it could be attached. anyone know anything about replacing the motor?

 

[m3x1c0]

We have lift off! Used some of the plastic push-through things to mount the new fan on the radiator. Car stays nice in cool in traffic! After a few blasts around the countryside she did tend to stay a little hot (one bar above the midpoint on the temp gauge.) I'll be keeping my eye out for a new taurus fan as I'm sure that will be more efficient. I will post my diagram that I made after studying the wiring in the car. Turned out that not only was the fuse blown but all 3 relays were indeed toast. 2 of them are rated at 70 amps! They were not cheap to replace.

Onto my next set of problems: leaking oil from lower intake, stupid door handles keep falling off, The tires are too wide and the car so low that they are getten chewed up by the rear fenders when I have chubby friends sitting in it (Me and my girlfriend are light enough that it wont rub ),and the damn hood is impossible to close sometimes.

 

[FoxMustangLvr]

1) What is controlling your fans? The ECM? What ECM is it?
2) What CFM is your new/used fan rated? Maybe it's not moving enough air.
3) Roll your fenders, do a search on it.
4) Adjust your hood strike/latch if it's not latching.