electric fan switch

I cant get an electric fan switch to work in a 327 sbc. I have tried 4 different switches and recently put one in that I know worked on a friends car. The fan switch simply goes to ground to make the fan come on - correct. I can disconnect the switch wire and touch it to the switch housing and the fan comes on so I know that the switch is infact grounded. Why doesnt it work????????

 

Are you talking about a toggle switch or a thermostatic switch? Also, are you connecting to the fan motor directly or is there a relay in between?

 

Is your fan grounded?

 

Get A sending unit from a 70*S Mopar FWD & put in the lower Rad hose Get a piece of pipe from your local muffler shop Braze a fitting to fit The unit ( Batt full time that when you park it will keep running until the coolant does it's Job) Ie put a cast iorn skillet on the stove heat it up if you ain't stirring the gravy It will BURN !! I will show a patent # that I own for automatic pressure RAD cap

 

Make sure your temp sending unit is for an idiot light and not a guage if that is how it is wired to come on.The sending unit will have to be an off/on type but for a lower temperature than overheat.

 

I have a dual elec fan, the low speed I run off a relay and it runs when the car is on, the high speed relay is fired by a sending unit that activates at 200 or so and goes off at 185. IMHO switches for elec fans are asking for trouble, for lots of reasons.

 

The old Omni & Horizon Had them Basically A on _off switch @ 180" turn On & Turn off Put it where ever you want to I have found the lower hose works best

 

Where is the switch mounted exactly? I had a freind put his in the rear of the intake. There was not enough water flow to heat the switch up and his car would overheat. He put the switch in the front of the intake manifold and it worked fine. I ran mine in the cylinder head and never had a problem. Maybe you have an air pocket and it's not heating up fully.

 

thermostat housing behind the thermostat.

 

i use one on my '47 that has a separate ground wire.

http://www.hotronicsproducts.com/store/product_info.php?cPath=7&products_id=27

 

How much thread tape or sealant are you using on your sender?

 

put an on off toggle switch on it and go

 

Using the same one on my 38

 

http://www.neow.org/images/elecfan/schematic.jpg
http://www.neow.org/electricfan.html
try those

 

I didnt use any teflon tape and it is screwed into the intake beside the thermostat housing. Like I said it will come on when I remove the wire from the switch and touch it to the housing so I know that it is grounding. Cant put it anywhere else double hump heads without any holes. I know that there is coolant flowing past it.

 

Try using a relay, have the switch provide ground to the relay coil, and the relay contacts provide power to the fan itself.

Are you sure it's a temp switch, not a gage sender?

 

that sounds like a goood place for it, what temp is the switch and is it the correct kind, pretty much anything late model at the yards will have a thermal switch for the fan, just do some looking around and hope you can find one with the correct threads, as far as grounding i use permatex high temp thread sealer, as you screw in the sender the wedge effect of the threads pushes away the material,and you get a good ground, not so with teflon tape. I've never had a ground problem with using this on senders.