Electric fans?

[killthewabbit]

Anyone else running electric fans on their truck? I have a goofy symptom that I'm working my way through. I fixed a problem yesterday where I had torched a fusible link and only one of my fans was kicking on. Now (and maybe before too) it seems like the fans kick on when it's pretty hot (just over 220, but my temp gauge) and kick off again pretty quick, like within a few seconds.

I'm troubleshooting now is my cooling fan system, and I've fixed all the way back to my thermostat that feeds power to the relay to turn on my fans. I disconnected the thermostat and jumped a wire from the battery to the terminal on the relay side and the fans kicked on fine and stayed on for a long time. The other side of the circuit goes underneath my dash to the fuse panel.

My questions -

1.) What are yall using for a thermostat? I'd like to have them kick on a lot lower than they do now, but they used to kick on pretty low, like 210 or so. I think maybe my thermostat isn't as effective as it used to be.

2.) How is your thermostat placed? Mine looks like a meat thermometer and it sticks through the radiator fins at the upper driver's side of the radiator. Is there a better place to position this thing so that it works a bit more accurately?

Thanks in advance for the help.

[Twisted78SS]

I am running electric fans as well, my thermostat mounts into the manifold and is a non adjustable with a 195 on and 180 off setting [I think]. You can see it in this pic, its on the front left side of the manifold. it uses two blade connectors to go in-line to the relay. I used to have a bulb style that mounted in the radiator fins, but it was not all that accurate IMHO.

[gchemist]

I use a Painless Wiring harness.

The sensor screws into the head. I use the passengerside head. The fans kick on at 195 and turn off at 180. The sensor works great.

[Mickey_D]

You could also try using a snap disc from an HVAC shop. They have all different temp ranges. You could get one that fell within your requirements and solder it onto the top tank of your radiator, then hook it direct between ignition power source and the relay control side.

[piecesparts]

I have two trucks with the dual SPAL fan setups in them. The 84 has a temperture switch in the intake that feeds the control relay that turns the fans on. I fed the circuit from that to two heavy duty fan relays so that I don't overload the contro relay switch. When the tempo switch closes, both fans turn on. The 91 Silverado has the same dual fans, but the controller is a SPAL PWM fan switch. It is tapped into the temperture switch that feeds the truck's computer and turns the first fan on at one temperture and the second fan on when the temperture gets to high. This is the best setup so far, but is a little pricey. I have purchased another one of these switches for the 84 truck so that I can control the electrical load on my charging system.

The temperture probes that fit into the radiator fins or into the radiator return hose are limited on their abilaity and can be improved upon greatly by looking into other setups.

Check out BE COOL www.becool.com for temperture switches or Centech www.centechwire.com .

[swb85]

I've got a Be Cool controller for my electric fan, and the thermo switch actually just died this weekend. It only lasted 9 months. I just took the ground wire off the thermo switch and ran it to a switch in the cab so I can turn the fans on/off manually.

[killthewabbit]

I used to run manual fans too. I'd like to get back to my auto ones working again. I never messed up and left the fans on or anything, but I'm sure it would happen eventually.

Twisted and gchemist, all the sending units I've seen look to be single blade ones like this one from Summit

http://store.summitracing.com/partde...5&autoview=sku

I'm not sure how that would work. I thought the sending unit completed a series circuit which would send power on to the relays to turn the fan on. Am I missing something? The install on those would be a lot cleaner, but I've never seen one with two blades.

[killthewabbit]

Different view - it's a different temp for on/off, but looks the same.

http://store.summitracing.com/partde...5&autoview=sku

[moneyeater]

I´m running dual electric fans with a thermoswitch from Ron Francis Wireworks wich sits in the intake next to the thermostat!It works great and between 161° and 176°,The temperature is about 15° higher in the intake so the switch with the lower temps is good.
Otherwise it should be mounted in the head where the sensor for the tempgauge sits!
Look here :http://wire-works.com/accessories.php
Its the AR-33!

[killthewabbit]

Moneyeater, is that one a single blade or double? How do the single blade sensors work?

[pcmcobra]

My setup:
LS1 fans, and FAL controller

Controller not show in pic, but I installed it on the core support next to driver side headlights. It uses the "probe" type.
Works great for me.

[Pyrotechnic]

I bought the Jegs house brand kit which has a sensor that screws into the head or intake manifold. Works great so far. I chose this kind because a lot of GM cars used the same style of switch in the 80's and early 90's so I figure it's a simple and proven design. Also wired a switch in the cab to turn them on manually.

My dad had a Flexalite controller on his truck. Never seemed to work correctly and eventually burned up and melted lots of wires. Expensive junk.

[Mickey_D]

killthewabbit, the single blade ones complete the ground. 12V switched power goes to one side of the relay control circuit. It then goes from the other side of the relay to the thermal switch. The thermal switch then completes the ground side through its casing.

Much like your alternator does.

[piecesparts]

Originally Posted by swb85

I've got a Be Cool controller for my electric fan, and the thermo switch actually just died this weekend. It only lasted 9 months. I just took the ground wire off the thermo switch and ran it to a switch in the cab so I can turn the fans on/off manually.

I went through Be-cool and they suggested the SPAL unit. It is definitely the "Cat's Meow" of fan controllers. I have had mine in the daily driver for two years with no problems.

[killthewabbit]

Originally Posted by Mickey_D

killthewabbit, the single blade ones complete the ground. 12V switched power goes to one side of the relay control circuit. It then goes from the other side of the relay to the thermal switch. The thermal switch then completes the ground side through its casing.

Much like your alternator does.

Ah, OK. That makes sense.

Pcmcobra, where do you have your probe installed? My current one is at the top driver's side of the radiator. Is that a good spot to put the next one?

I think I'm going to order this one at AutoZone here in about an hour, unless one of yall has encountered a serious problem with the Painless unit.

http://www.painlessperformance.com/w...rchField=30112

I hate to switch to an engine mounted single blade sensor since mine's already wired up. This way I can control when the fans turn on myself. I've heard the brand name Painless before, so hopefully this is a decent quality unit.

Thanks for the help, fellas. If yall have a horror story about Painless, I'd love to hear it. Otherwise, I'm gonna go order this one and install it.

[pcmcobra]

Originally Posted by killthewabbit

Ah, OK. That makes sense.

Pcmcobra, where do you have your probe installed? My current one is at the top driver's side of the radiator. Is that a good spot to put the next one?

I think I'm going to order this one at AutoZone here in about an hour, unless one of yall has encountered a serious problem with the Painless unit.

http://www.painlessperformance.com/w...rchField=30112

I hate to switch to an engine mounted single blade sensor since mine's already wired up. This way I can control when the fans turn on myself. I've heard the brand name Painless before, so hopefully this is a decent quality unit.

Thanks for the help, fellas. If yall have a horror story about Painless, I'd love to hear it. Otherwise, I'm gonna go order this one and install it.

My probe is in the same place....and btw, flexalite updated their vsc controller last year, with better/more heatsinks, I contacted them, they sent me and brand new unit. I heard/read some posts in other forums about the vsc, but it seems this update has cured the problem. Mine has never given me any trouble.
As soon as I do my 6.0 swap, I am ditching the controller and going with the pcm "controlled" with the harness. Just for simplicity, and less wires...

[moneyeater]

Originally Posted by Mickey_D

killthewabbit, the single blade ones complete the ground. 12V switched power goes to one side of the relay control circuit. It then goes from the other side of the relay to the thermal switch. The thermal switch then completes the ground side through its casing.

Much like your alternator does.

That is the way mine works too!