This might be the one i go with.

 

No..atleast on a cold start it doesn't turn on right away. Its so quiet that its hard to tell when I am driving, even idling because of the exhaust. I might run an LED into the cab so I know when it is active

 

Unless you add a circuit to tell you that the fan is actually running (using power), the LED will only tell you that the power is ON. In my opinion, the easiest approach would be to add a thermal switch that comes on at a "concerning temperature" and wire that to an alarm.

 

If you want to know your engine temperature, your superchips tuner can be used as a real time display. go to advanced features and data logging. I leave mine plugged up and have it stuck to the dashboard. it can tell you ANYTHING!.

 

Switching to ground is the way you'll find most things designed these days - I've found myself mixing my designs, but with computer control it's often easier for a number of reasons to close the circuit at the ground.

Don't keep it that way, a switch isn't designed to stand up to that amount of power - the contacts will either fuse or burn off relatively quickly. You should use a relay if you want to switch to a mechanical control. Do you know if that Derale thermal sensor is actually a sensor or a switch? If you're interested in making yourself a mechanical (relay) controller, I can give you a quick layout and parts list of what I'd use myself.

The Painless fan controllers can be purchased for either a single or dual fan. If you want to upgrade to either a 2 speed fan or to 2 fans and use a mechanical controller, you'll need some additional parts (at least 2 relays and 2 thermal switches). The full fan power is generally "kicked in" when the AC clutch fan is activated - this signal is used to switch your system to hi-speed. If you feel you want to go this way, I can provide a simple layout that will work.

I would recommend going to a local auto salvage yard and getting a used fan that will fit your needs - they're a lot cheaper and more dependable than the after market variety.

 

Yeah ^ I have a scantool that displays all the live data. It's very convenient..I mount it on my iPod dock bracketron thing and analyze stuff while driving. It's quite the distraction as well!

 

I am curious if the stock sending unit and the derale sending unit are standard. If I purchase another kit, can it be expected that whatever sending unit the kit comes with will be compatible with the other two sending units.

 

Which Derale model do you have, it makes a difference if you have (had) a relay based system or a solid state system. Normally, without any "smarts" in the box, you would use thermal switches (these turn on at a specific temp and then turn off at about 10 -20 degrees below the turn-on value, this gives the fan a chance to run/cool for a bit longer). A unit that has some smarts would (or could) look at the signal output from a temperature sensor (sender unit that changes resistance as the temp goes up). Its usual for the sender to decrease in resistance as the temp goes up - this changes the voltage on the line to the ECU as well as to a smart fan controller and allows them to look for the signal values needed to switch the fan on/off, or to turn it on and "bump" up the speed as the temperature increases.

I'm planning to test a Spal PWM fan controller and don't want to hook it up to a vehicle, so I'm laying out all the parts on the ground and will be using an old jeep temp sender and a heat gun to warm it up to the point where the unit will cause the fan to turn on, so what I'm saying is that most OEM temp sensors/senders are very close to the same & their connectors appear to be the same, so if your Derale unit used a sender, what you have is most likely good to go, but if your Derale unit used a thermal switch, you will need to leave your sender alone and use a switch for the controller.

If you plan on keeping your current fan, it would use less than 30 amps and would be compatible with a Spal unit so instead of spending your money on another possible melt-down, I would suggest that you look around for a new or used Spal unit. Maybe some of the people on this site that use a Spal and are interested in upgrading to something else would be willing to sell you their working system with the manual. This should work pretty well for you and give you more features and fan control than what you had with your old unit and the cost of a used Spal shouldn't be more than what you'd spend on a Derale. With the Spal, you could use your OEM temp sender and also have a connection to the AC that would cause the fan speed to go up when the pump clutch was activated.

 

I bought a cool water temperature gauge from pepboys for $25 that i will install this week.

 

pics???