dtk132

Hi Everyone.
So Im trying to figure this out, but could use a little help. I got a p/n 3653 Hayden fan switch that uses a probe against the upper radiator near the hose and a seperat 30A Relay I bought seperately. I am using the stock v6 single fan to cool my 1st gen 350 v8 carbuerated.

I posted what should be a helpful diagram I found for wiring this Hayden fan switch because the instructions it came with were horrible and could not read them the ink was so bloged.

Take a look at the picture first. I have everything hooked up so far correctly except 30 and 86 on the relay. Where should these wires go? What ignition wire on 86 terminal and i guess 30 terminal is supposed to go to the battery. But cant that go to just a 12V constantly on wire somewhere in the interior instead? If so what are some examples of both 30 and 86 i can splice this wire into.

Another thing, I have a fuse I plan to put inline with the terminal 30 on relay .. what type of fuse should I use? (ex-10amp,30amp, 40 amp?)

And 1 last thing I want to have an override on/ off manual switch under the dash just incase the sensor doesn't work.. would this be connected on terminal 86 or 30? and how?

Thanks!

camaronewbie

OK ...

1) the relay needs to be under the hood, not in the car interior.
2) that Hayden unit is not wired to have a sperate switch to activate the fan, it's designed to be tempurature run only. There's no relay required with that part - so I'm lost as to why they gave you a diagram showing a relay when a) a relay is not required, and b) they don't help you wire in a switch anyway.

But have no fear, we can still do a manual ON switch. I'm going to explain where each wire goes to/comes from, so that you can use the controller AND a seperate switch as well.

Now - beforehand - if Hayden sent you any other information, please include - maybe there is an easier way than what I propose - but this will work if no other info available from Hayden ...

1) switch - on your fuse block, there should be an empty slot marked IGN - just a single slot - can't put a fuse in it b/c fuse has 2 tabs and this is only a single slot. Crimp a 1/4in male spade connector on a wire, insert into slot. This wire connects to your switch. If switch is iluminated (good idea), then your switch has 3 prongs, power in, power out, ground. Wire from IGN fuse slot to power in, connect a ground, and then wire out from power out on switch to under hood. Done with switch.

OK - now look at my attachment. Here's the operation ...

With the relay not activated, battery power runs through the relay from 30 to 87a, and out to the fan controller. Fan controller does it's normal thing - when it gets hot enough, it sends that power out to the fan - everything works as it should.

Now - with your switch - you turn it on. 12v+ comes from IGN slot in fuse box, to the switch, illuminates the switch (since it's grounded), and the power go out to the relay at 85. Since relay is grounded at 86, the coil in relay activates, which makes the throw change position from 87a to 87. This changes the battery power direction from the controller (87a) which only activates when it reaches it's temp, directly to the fan (87) making it come on and run as long as the switch is on.

So - you need to splice into your existing positive fan wire, 2 new wires, the one from the Hayden controller, AND a 10ga wire from relay post 87. The positive fan wire will be black with a red stripe (the neg fan wire is solid black).

Any small wire (like 18gauge) can be used for the switch wiring all the way to the relay. You want nice heavy 10ga wire from relay to controller, from relay to battery, and from relay to fan wire. There is no fuse needed anywhere in this setup. The relay does the protecting. If concerned, you could put a 10amp fuse between switch and fuse block. But the relay will blow if more than 30 amps is drawn through it, so it is it's own safety device.

This make sense? Let me know if you don't understand something. Relay available on the shelf where the fuses are at any auto parts store, about $8.

camaronewbie

OH - BTW .... I get $50 an hour, 1 hour minimum. Can paypal me.

Seriously, I'm just kidding ... I'm glad to help - I'm an idiot with a dangerous amount of knowledge, and I love tinkering with relays!

dtk132

Awesome ! Thanks a lot
Thats very helpful and a good write up

3 more questions:

1) Am I okay to run the relay and no fuse? wont it produce more than 12v and will that burn up the fan motor or the controller?

2) Where 30 from the relay goes to the battery. Can I splice this wire into another wire somewhere in the engine bay or should I just go directly to the battery?

3)at what temp should I have the fans kick on? like 190ish?
The controller does not have any markings as for temperature just a screw to loosen or tighten to adjust the sensitivity of temp.

Again,
Thank you!

camaronewbie

1) No, relay can't make more than it gets, all it gets is 12v. Your really fine here with no fuse anywhere if you wire like I showed, I promise. Besides, it's amps that fry wires, not volts.

2) No - make sure the wire from 30 goes directly to battery, or the starter post where battery pos wire attaches, or to the power distribution block beside radiator (if you have). This wire will be handling the high amperage draw of the fan, thus needs to connect directly and be 10 gauge wire.

3) If you have a 180 thermostat, I'd have fans start at about 200. If you have a 195 thermostat, maybe fans on around 210. You want the thermostat to open BEFORE the fan comes on.