Adjustable temp sender

butch27 · October 08, 2008, 09:03:09 PM

I'm putting and adjustable temp sender on to run the electric fan (going through a relay). Will I need to fuse both the Fan and the new Temp sender? I'm using #86 as GRD. Thanks :?

enjenjo · October 08, 2008, 09:13:21 PM

You could run both off the same fuse, but one big enough for the fan, would too big for the switch.

WZ JUNK · October 09, 2008, 06:39:36 AM

Some adjustable fan temperature switches do not require a relay. Which brand do you have?

John

butch27 · October 09, 2008, 09:25:47 AM

It's a no name BUT is does NOT show a relay. The sensor tube goes into the radiator petcock hole. It only says use a 20 amp fuse.??

model a vette · October 11, 2008, 10:00:02 AM

Quote from: "butch27"It's a no name BUT is does NOT show a relay. The sensor tube goes into the radiator petcock hole. It only says use a 20 amp fuse.??

Be careful using a 20 amp fuse. I had one "un-solder" one end, on a glass fuse, leaving the fuse looking ok. I rolled into Louisville in August with the fan not working. Not good!
I think the old style glass fuses will unsolder if the current is near their rating but not over it.
All of this was with a sensor tube like the one you are talking about.
I switched over to a block sensor from a Chrysler minivan and used it to ground a relay. The power for the relay comes from the ign switch in the on position. The power for the fan, thru the relay, is from the starter battery terminal and has a fusible link.
The Napa catalog shows sensors with different turn on temps so you can get one in the temp you like. I chose one that turns on at a low temp as my electric fan is the only fan.

butch27 · October 11, 2008, 02:08:46 PM

I like that idea but I can't find a in block place to connect on my 302" Ford.?

model a vette · October 11, 2008, 11:48:35 PM

Quote from: "butch27"I like that idea but I can't find a in block place to connect on my 302" Ford.?

I also ran into the problem of finding a place to install the sensor. I had been running two temp gauges for a test. I pulled one to install the sensor.

You could install a fitting in the heater pressure line on the manifold that would split off an extra hole for the sensor.

The minivan sensor I'm running was actually installed in the bottom of the radiator from the factory. I think it was designed to read the water temp as it was exiting the radiator. I think that is why it was set to ground at such a low temp. I think it is set at 170 or 180.

butch27 · October 12, 2008, 08:58:34 AM

The HOT connection on the sensor has 2 prongs. One says normally open and the other says normally closed. Which one should I run power to?

enjenjo · October 12, 2008, 09:34:44 AM

Quote from: "butch27"The HOT connection on the sensor has 2 prongs. One says normally open and the other says normally closed. Which one should I run power to?

Depends on how you are wiring it. Normally open, will be open until the engine warms up, and then close. Normally closed with be closed until the engine warms up, then will open.

If you use a relay, and I suggest you do, you can set it up with the normally closed terminal, so the relay has to have power to shut the fan off. This will make the fan run all the time if the switch fails. If you wire it NO, the fan won't run if the switch fails.

Without a relay, you are running all the fan power through the switch, and they usually don't last too long.

Also, if you have AC, a relay will let you set it to run the fan whenever the AC is on.

If you need a wire diagram, say so, and I will post one.

butch27 · October 12, 2008, 10:22:37 PM

Man do I ever need a diagram. I hate wiring. BUT I'm getting there. Thanks

enjenjo · October 12, 2008, 11:09:04 PM

I'll get one posted tomorrow.

tom36 · October 13, 2008, 09:23:48 AM

I used one of these on my 36-
http://www.speedwaymotors.com/p/2356,,_Electronic-Cooling-Fan-Control.html?itemNo=adjustable%20fan%20relay
Built in relay, fully adjustable on/off and no probes or sending units to install. I have the control mounted under the dash and if I want to manually turn the fan on or of, just rotate the adjusting knob. Green LED for off. red LED for on. Tom...

enjenjo · October 13, 2008, 08:03:10 PM

Here is one way to wire a relay, so it will work with your temp switch. With this setp, you will need to set up the switch normally open.

The AC clutch wire will split off to the relay at the clutch, so the fan will run whenever the AC is on. If you don't have AC, then ignore it.

I included a picture of the relay I use, you can get them most anywhere. They have 5 terminals. Using the relay will also stop the engine from running after the ignition is turned off, with the fan on.

butch27 · October 13, 2008, 09:48:56 PM

Thanks Frank: Mine is bare minimum - No A/C or heater. I just feel better using relays.