Electric fan Question

[Jeremiah Morgan]

I bought a Mark8 fan for the ST...I have seen and heard of several ways to hook it up..

The one in the projects here, Using a Hayden thermo switch..OR Can't I use the Temperature sending unit and hook ground to it??? What is the best but easiest way??



Thank you in advance..

 

[Jeff C]

You mean just tap into the factory temp switch w/ a ground? So your fan will be on all the time? That will kind of negate the gains b/c it will constantly draw on the alternator.

 

[Todd Z]

The Factory switch can not Handel the 20+amps that thing on the High setting will draw...



Ebay has $25.00 40 amp kits with the thermal probe and A/C bypass built in....



This way it is wire correctly and there is no chance of getting stuck...



IF you use the SPAL relay box you need to make a connection in the upper rad hose to screw in the temp sensor, a rad shop can make you the fitting...



The kit on Paul's truck I got off ebay....



http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&viewitem=&item=230151098776



Todd Z

 

[Jeremiah Morgan]

Thank you..I will get the Hayden one like it at work..its same price...

Thanks for the input...

 

[Dan Long]

I've got a DC Controls fan controller for my fan that I will be installing when I do my V8 swap. If you haven't seen them, check them out at www.dccontrol.com . They're a little on the expensive side, but if they work as advertised it should help keep the noise level down and reduce the current draw.

 

[Jeff C]

Dan,



How quick was the s/h on that unit? It's originally what I wanted, but at the time I wrote the project, he was having problems filling the demand, and many many people advised me to stay away from that company b/c of their lack of customer support, communications, etc.

 

[Richard L]

Electric fan Thermostats are designed to work on Radiator coolant temperatures, and are designed to handle the load of the fan. The engine temperature sending unit is not. Also, the Fan thermostat is a simple on-off, and the ST is equiped with an analog sending unit that changes voltage with the temperature to move the needle on the temp gauge.



Fan Thermostates will usually have 2 settings to turn the fan on and to turn it off.. Typically the Fan may be set to come on at about 190-200, and shut off at 180 or less. Use a thermostat designed for controlling the electric fans, but I would recommend using an override switch on or under the dash.



I have used electric fans on a lot of cars and have never had any fan fail, but I have had a lot of problems with thermostats failing. So I always wire in a manual switch to bypass the thermostat which allows me to turn on the fan if the thermostat fails. That will usually prevent you from being stuck on the side of the road with an overheated engine because the fan controll thermostat failed



...Rich

 

[Todd Z]

Just FYI,



The ebay kits do not allow you use the A/C bypass and a manual bypass switch....



You will wind up back feeding the AC system....



You will have to come up with something, maybe on the low setting, BUT do not run the low and High at the same time... You will damage the motor...



Todd Z

 

[Gavin Allan]

Use a diode in the circuit to prevent back-feeding the AC.

 

[Dan Long]

Shipping was a little slow on it, but I wasn't really in a hurry. The nice thing with it is you wire it to the high speed only on the Mark 8 or Taurus fan (what I got) and let it control the speed for you. Gavin is also correct, put a diode in the A/C wire to prevent backfeed to it.

 

[Richard L]

Always run and electric fan from a separate relay. That will allow you to prevent back-feeds to the AC.



I'm not sure how or why there would be anything that would prevent hooking up a separate manual override switch since it is just steps over the thermostat and if you use a relay to power the fan and the AC/thermostat/and the override switch as the tricgger for the relay, there should be no problems with feed back. On some models you may have to run the AC trigger through a separate relay, but even that is not major problem. relays are cheap and the most practical solution for isolating the fan and preventing back-circuits.



...Rich