My $5.00 fix

[Andy4639]

Ok guy's I have been searching for a answer to my fans running all the time when I'm on the road at speed with the AC on. We all know that these fans are expensive and burning up $300.00 worth of electric fans isn't going to be fun no matter when they go out, so I finally think I have it figured out. I ran out of time so I'm going to test drive it tomorrow after work and see.
I even came up with a little light to tell me if it's working are not. I don't know if I'll keep it in the truck are not we will see. Really depends on how bright it is when it's on.
Ok here is what I did:
I wired a micro switch into the AC on wire to the relay I added a few weeks ago. Like in the picture with the arm extended with a flap on it to catch the air and turn off the fans once it see's enough air flow. I have it mounted inside the grill. Hopefully it has enough wind when driving it to shut off. I bolted it in place and put my fan in the front of the truck and it shut off so I hope it works. Adjustments will be done by either making a bigger paddle are trimming the one on it now.

[BugzC10]

Subscribed...it will be interesting to see how much your temperature changes "at speed" when your fans stop pulling air when the micro switch cut the power.

[MARKDTN]

Can't speak to an LS engine control, but on a TunedPort you have to have a high pressure a/c switch to tell the fans to turn off at speed. If the circuit is open then the fans run as long as there is power to the a/c. If the pressure is not high then it sends a ground and the fans do not run constantly.

[davepl]

That's a cool idea... as soon as I saw it, I knew what it was for, but wouldn't have thought of it!

Did you ever consider that will road air flow the fans aren't being worked very hard anyway because the motors are being assisted by the airflow through the grille? I don't know if that actually makes them last longer, but it might take load off them. Or maybe they have the exact same load and just spin faster, I don't really know...

[Andy4639]

Originally Posted by MARKDTN

Can't speak to an LS engine control, but on a TunedPort you have to have a high pressure a/c switch to tell the fans to turn off at speed. If the circuit is open then the fans run as long as there is power to the a/c. If the pressure is not high then it sends a ground and the fans do not run constantly.

MARKDTN,
I had a tuned port for over 15 years but I ran the engine clutch fan all the time. I never had electric fans. Well I did but had it turned on by the AC fan switch not the PCM.

The LS fans work off the ground of the PCM also if the water temp reaches 185*.
If I have the AC on it sends the ground signal to both of the fans to come on no matter what the water temperature is. It over rides the PCM ground.
BugzC10,
The water temp pretty much stays at 179* all the time when at speed weather the AC is on are not. The fans hardly ever come on when driving it only in traffic are idling.
davepl,
Over heating isn't why I did this it was purely to keep the fans off when I'm moving which I hope will extend the life of them. The fans are rated at 3100CFM when both are running.

I looked for several weeks into what was out there for this kind of setup and everything was way more than I wanted to spend on it.
This is simple and cheap.

$269.99



$119.95



$5.00!
Over all it does the same thing as the top two with less things to go wrong with it. If it fails all that happens is the fans stay on all the time.
I'm going to wire the small light up tonight to let me know when the fans have power and when it goes off it tells me the fans are off. Simple!

[Andy4639]

Just finished up this little mod!

Wired a small green light into the dash so I know when the fans are running. The paddle cuts them off @20-25 MPH and back on when I slow down as long as the AC is on. When not the only time they will run is @ 185*! Couldn't be more happier.

[Ironangel]

Originally Posted by Andy4639

Just finished up this little mod!

Wired a small green light into the dash so I know when the fans are running. The paddle cuts them off @20-25 MPH and back on when I slow down as long as the AC is on. When not the only time they will run is @ 185*! Couldn't be more happier.

Thats bad ass Andy! "Mikey Likes It!" You better get a "patent pending" on it before I do!

[Andy4639]

Originally Posted by Ironangel

Thats bad ass Andy! "Mikey Likes It!" You better get a "patent pending" on it before I do!

It's a done deal as we speak!

[Dave in Ozark]

CLever use of a sail switch and infinitely adjustable. Very resourceful

[Z10]

Originally Posted by MARKDTN

Can't speak to an LS engine control, but on a TunedPort you have to have a high pressure a/c switch to tell the fans to turn off at speed. If the circuit is open then the fans run as long as there is power to the a/c. If the pressure is not high then it sends a ground and the fans do not run constantly.

I'm using a high pressure a/c switch on my FIRST TPI 350. Here's a couple of pics.

[jdw]

I wonder what the lateral tolerances of that switch are ? I don't think the design parameters included this. It's a really cool idea, though. I imagine it flicking on and off all the time on a bumpy road, and that would be rather hard on the fan motors and fuses. I wonder if a speed sensor and a relay might not accomplish the same goal in a different manner.

[Andy4639]

Originally Posted by jdw

I wonder what the lateral tolerances of that switch are ? I don't think the design parameters included this. It's a really cool idea, though. I imagine it flicking on and off all the time on a bumpy road, and that would be rather hard on the fan motors and fuses. I wonder if a speed sensor and a relay might not accomplish the same goal in a different manner.

Micro switches are spring loaded to stay in the position they are in. They are used in every golf cart on the market for all kinds of stuff and they will not bounce. They are tough little critters! They work for years with no problems. I have had 1970 golf carts in the shop that the micro switches where still performing.

I don't thing it will be any problem at all.

[notsolo]

"Brilliant Idea" Andy!

[Andy4639]

Originally Posted by notsolo

"Brilliant Idea" Andy!

Thanks!