Powering the electric cooling fan

[Cyberpyr8]

I bought an aftermarket fan for my 79 Spit since my original fan was dead and bent. The dilema I am running into now is that I can't get power to it or find a power source that will cutoff when the key is off.

I tried hooking it to the old leads and it won't spin the fan at all. I have been looking for somewhere that would cutoff when the key was cutoff but there aren't many I can find with enough juice to make the fan spin full speed. Anyone else put one of these in and if so where did you draw power from?

 

[TR3driver]

My advice would be to add a circuit to power the fan. They draw a lot of power, and it's not a good idea (IMO) to add that load to the ignition switch. More work now, but less trouble in the future if you do it right.

Starting at the starter solenoid, add a heavy-duty in-line fuse holder and a heavy wire (12 or 10 AWG) to a convenient place to mount a relay. The old leads will likely supply enough power for the relay coil (so your new fan will turn off with the switch), and the contacts will provide maximum power to the fan.

Ask at your FLAPS, they may have a "fog light installation kit" that has most of the components you'll need (relay, socket, wires, fuse holder) for less than the individual parts. The switch & bracket are a bonus; you can use them to add an override to the fan thermostat if you like or toss them in the parts bin.

 

[Cyberpyr8]

Thanks TR3. I drive this car almost every day so I want to do it right. I sit in traffic and I don't want the car to overheat because I took a shortcut!

 

[frankenstang57]

I agree, you don't want to run the fan off of the ignition switch, you'll cook it.(the switch) Fog light install kits are the easiest source for components to hook up a circuit with a big draw. Another thing you can do is buy a thermostatic switch to cycle the fan on and off just like new cars. I just picked one up and am planning on installing on my Stag later today. You don't really need to run the fan all the time as they become pretty useless at hwy speeds. The thermostatic switch route will be alot easier on your charging system in the long run. They run about $25 or so and comes with all the wiring/fuses/relays/instructions. Either way will work, it's just one is "slicker" than the other. Good luck! /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

 

[Cyberpyr8]

I did buy one of those thermostats as well.

I wasn't going to run off of the ignition switch directly, I just wanted something that would cut off with the ignition. I had a fan on an old Ford run the battery dead because it didn't cutoff. I have been sort of leary ever since!

 

[TR3driver]

I agree, a thermostatic switch is necessary as well. But not all of them come with a relay ... I assumed from the question & the referenced VB page that you had one of the ones without a relay.

When I added an electric fan to the Stag, I found an adjustable thermostat that included the relay, wiring, etc.; but it was almost $50 and didn't include the fuse to go at the starter solenoid.
DeRale adjustable fan thermostat

 

[RonMacPherson]

do you have any open terminals on your fuse box? I prefer to take the wiring from the fuse box as it lessens the chance of a wire coming loose and goofing other circuits that are not related to the wire coming loose. I have seen many aftermarket installations of alarms, stereos, etc. where the installer(professional at times) will pickup from the starter solenoid and the installation causes other problems down the road(loose terminal, terminal open to corrosion, etc.) As I am a mechanical breakdown inspector I look at vehicles every day and get to see enough installation errors that I cringe, sometimes, at what people are driving.

If you have an empty fuse holder on the fuse box, you can jump it so it's powered when the key is on, take a test light and turn your switch on and off and isolate the circuits(or look in a wiring schematic. I know that 6's come with an unused fuse slot, dunno about spits. A good 30 amp relay can be purchased for around 12 at most auto parts stores. Make sure you run large gauge wire to the fan from the relay, and power supply to the relay(12 gauge is what I use). And I've had a couple of the probe type sending units fail after a couple of years, so either a sending unit type(tee the temp sending unit you've got, or might have a water outlet plugged on the headd) or a backup override switch. Summit has a good little sending unit, in their catalog, that I can't find on their site, that fits right into the temp outlet by the tstat on my 6, might check with them.

 

[frankenstang57]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]When I added an electric fan to the Stag, I found an adjustable thermostat that included the relay, wiring, etc.; but it was almost $50 and didn't include the fuse to go at the starter solenoid. [/QUOTE]

I just paid $33.89 for the exact fan control at Advanced Auto... The boys at Summit are 'spensive. I think it's funny the put a fuse inline to the fan motor instead or to the battery.

 

[TR3driver]

The boys at Summit are 'spensive.

True. But I was in a hurry so bought what was on the shelf where I bought the fan. Their price was similar to Summit's (which I just linked to to demonstrate the kit I was talking about).

Wish we had Advance Auto around here. Supposedly the same company runs Western Auto in CA, but the nearest Western Auto is a half-hour drive from my house. Just discovered them last week ... sorta nostalgic to visit an old WA store, but there are probably a dozen other stores closer to home. And even though they were high on the fan controller (and fan), I like Clark's. The droid at the counter may not know what a Triumph is, but the manager does, and he can usually find me what I need.

 

[TR3driver]

I wasn't going to run off of the ignition switch directly, I just wanted something that would cut off with the ignition.

My apologies if I'm mis-interpreting ... but if the ignition switch will control it, then it is drawing current through the ignition switch, no matter where you tap into the wiring harness. The only way around this is to use a relay (or have one integrated in the fan control), so the switch powers the relay (which takes only a tiny amount of current) and the relay powers the fan.

 

[Twosheds]

Supposedly the same company runs Western Auto in CA, but the nearest Western Auto is a half-hour drive from my house. Just discovered them last week ... sorta nostalgic to visit an old WA store, but there are probably a dozen other stores closer to home.

Wow, I didn't know Western Auto was still around. Makes me nostalgic just thinking about it. Do they still sell Wizard tools? I ran across an old Wizard socket the other day and got all misty-eyed. Any Joe the Motorist's Friends still around? Sob...

Nostalgia isn't what it used to be...

 

[TR3driver]

Do they still sell Wizard tools?

Sorry, no idea. I didn't look at their tools.

Did have DOT 5 brake fluid though; and several Casite products on the shelf. Been a long time since I've seen a can of "Motor Honey".

 

[Cyberpyr8]

I got it installed last night. After putting the thermostat control in I have tested it and it seems to work great.

One more quesion though, should the fan blow through the core or should I pull? The fan will do both but since I have never had a working fan I wasn't sure which way it should be blowing. I think that it should pull (from outside the car into the engine compartment) since that looks like how the radiator was designed. But I had someone else say they thought that it should blow out across the core.

 

[TR3driver]

Definitely, the fan should move air in the same direction the car moves, ie from the grille to the engine compartment.

At higher speeds, most of the airflow comes from the car being forced through the air. This is a Good Thing, since your electric fan cannot move enough air on it's own to keep the engine cool at max power. But, if you install the electric so it tries to force air the other way, at some speed the two airflows will match force and you'll get no cooling at all !

 

[Twosheds]

But, if you install the electric so it tries to force air the other way, at some speed the two airflows will match force and you'll get no cooling at all !

Here at the High Speed Triumph Research Laboratory, we seek to benefit the Triumph owners of the world by adding to the knowledge base. To this end, we conduct experiments from time to time.

One of these experiments consisted of running an electric fan so that it forced air forwards through the radiator.

The result?

The temperature gauge pegged out and coolant puked from the overflow onto the paddock.

Just another example of our continuing search for the Truth; we leave no stone unturned.

 

[Cyberpyr8]

That's what I thought too. Thanks guys.

 

[tr6lover]

wire the thermostatic switch to an always hot power source. it only runs the fan when it gets hot enough to kick on so the fan isnt running all the time and therefore not drawing power all the time. if you wire it like this when you shut off the engine on a hot day it may run for a minute or two to cool te coolant in the radiator. this is how i set it up on my tr6 and i have no problems.
Randy

 

[Cyberpyr8]

wire the thermostatic switch to an always hot power source.

That's what I ended up doing. Today when I got to work it ran for a minute or so after I turned the car off and then kicked itself off.

 

[Cyberpyr8]

The fan works great. BUT...I drove the car home from work yesterday and I think I threw a rod. The motor is now knocking horribly. I guess it is time to do a rebuild! /bcforum/images/%%GRAEMLIN_URL%%/frown.gif

It really sucks because it had been running great. Any advice before I start would be appreciated.