electric fan

[floridasteve]

Please help me with this relatively simple question for you electric gurus. I found a loose wire in the truck. The fan was hot wired to work with a switch on the dash. It was wired hot from the fuse box to a switch. There are three terminals on the back of the switch. There is a blue and grey wire from the electric fan. Where do the grey and blue wires need to be routed to? Thanks.

[_Ogre]

your post is a little vague; heater fan or radiator fan? what kind of switch?
pics would help

[floridasteve]

Sorry, about that. The fan is an electric pusher fan mounted to the front of the radiator. Here in Florida things tend to run warmer than usual especially without a shroud on the truck. I have to follow the wires the whole way but I thought there was a relay in the line somewhere, The switch is just a lighted three prong toggle with three terminals on the back of it. I hope this helps with the explanation. It was hard wired to the fuse box because you would have to remember to turn it off. It was for helping the truck cool down when in traffic or stand still. Thanks again. I hope this helps.

[Andy4639]

Most of the time for a switch with 3 terminals:

#1 is hot from fuse panel.

#2 is hot to whatever it is you are running.

#3 is ground so the little lite in the switch is on when switch is on and off when power is off.

Normally!

[gmachinz]

You do not want to power anything substantial (10A or higher) through any kind of switch by itself. Those parts store switches are junk, and while you can use HD switches, I'd suggest running your fan(s) via tried/true temp switches and have them trigger relays to in turn handle the load to your fan(s). There are literally tons of diagrams on the internet so dona little research and see what best fits your setup-I have my own assorted fan diagrams but they are all dedicated for certain designs and aren't a generic one size fits all type diagram. There are many ways to wire them-dual speed dual fans, 3-speed single fan conversion, etc.

[Andy4639]

Originally Posted by gmachinz

You do not want to power anything substantial (10A or higher) through any kind of switch by itself. Those parts store switches are junk, and while you can use HD switches, I'd suggest running your fan(s) via tried/true temp switches and have them trigger relays to in turn handle the load to your fan(s). There are literally tons of diagrams on the internet so dona little research and see what best fits your setup-I have my own assorted fan diagrams but they are all dedicated for certain designs and aren't a generic one size fits all type diagram. There are many ways to wire them-dual speed dual fans, 3-speed single fan conversion, etc.

gmachinz, makes a good point.
the switch should only be for trigging the relays on fans are any other heavy amp draw in your truck.
I am bad about assuming everyone knows this when they ask question about wiring and such. This is basic stuff to most.

[gmachinz]

I'll illustrate a typical method In use for triggering electric fans-I prefer to use OEM fans and there are quite a few to choose from but I'll focus on the triggering aspect of it. I use (2) temp switches where each switch carries a certain on/off temp rating-in this case 212/202 and 228/218 and I mount them directly into an aluminum t-stat with dual threaded ports. I also add a HD ground to one of the housing studs to insure I have an excellent ground source. These switces activate pin 85 of each relay. Both relays are wired as:

30 Battery source (common 12V source junction)

86 Switched IGN source

87 Positive fan output 1 and 2

Both fan negative leads go to chassis ground.

This is a very basic dual fan setup and as I said here is a myriad of ways to wire fans based on fan type, desired means of activation, etc. I build quite a few variations of many style of harnesses for these trucks including electric fan assemblies so there are plenty of options. I'm working on a complete engine harness for my 406 S10 project using this triggering setup to run a set of Stratus fans which happen to be dual speed as well.

[Andy4639]

This is how to add relays for anything in the truck.

[Chance48]

I've been researching this wiring biz for a bit now. I've got the grasp on it but.... Is it best to just run inline fuses instead of trying to go through your fuse box for these high amp usage components? In my head I had a beautifully wired vehicle but now with all the relays I'm gonna need I'm afraid of having a messy job.

Example....in my mind now that I have an idea of what's going on. I'll have my head lights,e-fan,air pumps, hydraulic pump, (maybe for those two I'll use actual solenoids?), horn, fuel pump, and I'm sure I'm missing something....so, I'll use a junction lug to attach all these components, through the relay, to their main power source, using an inline fuse holder between said components and the main output from relay? And....for triggers for all these can I have an unfused power source? Or say....have a junction fused at 3 amps, this lug can run all my relay triggers, switched or constant? I'm kinda thinking I'll use relay blocks mounted at each component location, thus keeping high amp leads shorter and having a cleaner, better looking job.

Of course, all other wiring will go through a standard fuse box.


Please read this closely and tell me if my perception and my planned idea in my head is a good and simple approach. Thanks for your time.

Chance

[gmachinz]

A really nice alternative that I use on local builds is to source the aux. relay/fuse panel assembly from 93-97 f-bodies. Its located towards the front of the LH inner fender-it has provisions for several relay (8 I believe) as well as fuses for each and a single large stud for power input. Its very compact and is a very sanitary way to add a lot of under hood accessories relays/fuses and still look stock while being hidden.

[Andy4639]

Originally Posted by gmachinz

A really nice alternative that I use on local builds is to source the aux. relay/fuse panel assembly from 93-97 f-bodies. Its located towards the front of the LH inner fender-it has provisions for several relay (8 I believe) as well as fuses for each and a single large stud for power input. Its very compact and is a very sanitary way to add a lot of under hood accessories relays/fuses and still look stock while being hidden.

That is a awesome way to do it!

[Chance48]

Now I'm thinking I might just use the dodge box and harness. I'll retro it right into my new rig. It'll be time consuming but it'll be a solid setup. I'll decide when I go to actually do it, lol.

Thanks for the reply..

Chance