Electric Fan Help (B210)
Posted 12 March 2017 - 10:49 AM
You should wire it to a sensor that turns it on/off when needed. If it's on with the ignition it's running all the time and you may as well have left the mechanical one running. If you install a switch you have to remember to turn it on and off and what if someone else drives it? or stolen and over heated? There are any number of reasons why you may not be in or be able to turn it on. The last thing you want is to be watching the heat gauge and turning it on and off. To be worthwhile, something should be at least the same as the thing it replaces, if it has any advantage this is even better!
The main reason for a thermal switch is to make this totally automatic and and fool proof. I spliced a short length of pipe in the lower rad return line with a sender that energizes a relay connected to the battery. Almost never comes on except maybe stop and go or at the lights. After shut down there is always some 'heat soak' of the cooling system that is hot weather will expel some coolant out the over flow. The fan is always connected to the battery so it can even come on after I park to cool it down.
I pulled the sensor from a rad in the wrecking yard. I didn't worry about the on off temp as all vehicles run close to the same temp. Found a plumbing steel pipe bung with the same thread and drilled a hole in my pipe section and welded the bung in.
The fan is from a VG33 Xterra
Posted 12 March 2017 - 11:08 AM
May I add, that you should run the fan through a relay, so that the temp switch doesn't carry the full currant load.
Even though the fans are stated at only drawing 20-30 amps, use an 80 amp relay, as in-rush currant will kill the 40 amp relays in about 6 months.
The el-cheapo plastic electric fans last about 2 years, so in 1 year, 11 months, plan on buying a back-up.
Posted 12 March 2017 - 01:26 PM
Posted 12 March 2017 - 04:57 PM
Hook to the fusible link. That fan will draw a lot of current and even more when starting. Have power to it at all times.... it doesn't have to go through the ignition. If the key is off it may come on in hot weather for 2-3 min after you leave the car, so what? it will shut off.
Posted 15 March 2017 - 07:29 PM
The fusible link(s) are connected to the positive battery terminal. One usually goes to the headlamp switch, one to the fuse box and one to the ignition. Sometimes there is only one or maybe two. They are all live or 'hot' at all times.
Posted 17 March 2017 - 08:01 AM
If you have a temp sensor that turns on a relay to power the fans....
The electric fan draws a lot of power and even more on sudden start up. It does NOT need to be run through the ignition switch. It can be left with power on at all times just like your brake lights, horn, clock and interior lights. It just sits there until needed.
If the fan is on when you shut off the engine it really should keep cooling. All engines continue to heat up after they are shit off too. I've had my fan come on after I shut off the engine to cool the rad down.... big deal, it ran for maybe a min before shutting off.
If you connect to the auto choke or idle cut solenoid or the coil you risk blowing the fuse while driving.
Posted 17 March 2017 - 10:36 AM
Again mine is connected to the fusible link and hot at all times. The sensor only closes when the temp passes a pre determined point so there is no draw on the battery.
And again, if on the ignition switch the fan cannot come on after you shut the car off. The engine temp always goes up right after you turn it off. It can pass the boiling point in hot weather and expel coolant into the coolant recovery can.
Posted 17 March 2017 - 11:05 AM
B2fresh seemed really intend on using an ignition source on the relay I was just trying to answer his direct question...
Posted 17 March 2017 - 12:41 PM
I guess I'm just being overcautious.