1978 Std automatic with AC
About 7 years ago I installed a Flex-a-fit 3300 CFM electric fan. I used the controller that came with it. I've now gone through 3 controllers. The original controller is now called "Flex-A-Lite Adjustable Electric Fan Controllers 30332" on Summit Racing. They do not give the amperage rating on the controller, but the fan draws 18amps, running. Two of the controllers failed the same way. The connector for in coming 12volt line burned off.
The temperature sensor used is a probe that slips in-between fins on the radiator.

3 things:
1) I "think" I would prefer a temperature probe/switch that screws into the engine somewhere (any discussion would be appreciated)
2) The controller must also allow the fan to be energized when the AC is turned on.
3) I would like the "relay or switch" to be able to handle 30+ amps to be sure it can deal with starting current and what ever else might be there.

Has anyone used a different aftermarket controller that will last more than 2-3 years.

Thanks

(Also, I tried the Search using "fan controller" as the search item and the posts presented were all over the place, so I wasn't able to get info there)

 

I couldn’t be happier with my Derale PWM fan controller (stk number 16795) amazing!

 

And when ac is on the fans run at low speed. Car even runs cooler with ac on

 

If you use a PWM controller you need to make sure your fan is compatible. Lot's of info over on LS1tech.com.

 

A trinary switch on your high pressure line will kick your fan relay independent of your temp sensor.
Before I installed my EFI which now runs my fans. I simply ran a temp switch in the intake manifold triggering a 50 amp relay.
I still run a 50 amp relay, (Available in any auto parts store). And it's triggered by the ECU for my EFI that reads coolant temp through a sensor in the intake manifold and also triggered by the trinary switch in the high pressure line.
These temp switches like I used before my EFI that go to ground at say 190 degrees and go off when hitting 180 or there abouts are readily available in a variety of temp limits. Wiring up to a standard 50 amp relay is childs play.
I Currently run the C5 Corvette twin fans. the 50 amp relay seems to be more than sufficient.

 

Have had good luck with my derale pwm controller. It comes with a sensor for the radiator but you can get one the screws in iirc

 

If I ever feel the need to change what DeWitt's sent with mine, I'm going with the Derale too. Heard nothing but good things.

 

https://www.google.com/url?sa=t&rct=...kjuH_G_wC9KFb1

This is what I’m using, for all the concerns you’ve listed.

 

I too have been using the DeRale PWM 16795 on my C3 with it's 427 and it works and lasts just fine. I like the fact it will start at 50% speed/Power and slowly ramp up the fan speeds if/as needed. It is a well built part that has worked well and lasted more than a couple years on my Corvette. I have never seen any Voltage spikes, excessive wear and pre-mature wear.

Never heard of the DeRale 16797 but it looks like an improved version of the 16795. The DeRale products are quality oriented products with a good staff behind them to help in case of trouble.

The only PWM controller I have had problems with was the one made by Painless Wiring as it decided one fine day to let the smoke out and blew it's fuse for good.

 

Go with a PWM fan. Everything about it (other than cost) is a plus. Doesn’t hit your electrical system as hard, most have manual kick on switches, and most and AC triggers. Many are programmable. This is the controller we installed in my brother’s 68 Proform fan controller and its worked great AFAIK. He hasn’t complained about it. We mounted it inside the car and extended the leads to the fans. With any of these computerized controllers they MUST have a direct feed off the battery. Any noise or surges from the alternator etc will kill these things in short order. Do your research but you’ll find that the battery connection is critical.

 

Good points kossuth!

I have a pair of SPAL 11" fans on my dual fan shroud and when I became interested in the PWM controller I called and the tech support people at SPAL to see if the motors were compatible with a PWM controller and they assured me that they were and would not wear out any faster or be damaged by a PWM controller. It is wise to check to be sure because some motors are not able to work as well with a PWM control system. I would check with the fan manufacturer to verify it will work before using one.

Getting a good secure battery fed power setup is also critical to many of the PWM controllers. Mine are connected right to the battery even though my controller is within reach of the thermal sensor used by DeRale for my part 16795. I don't extend sensor wires like those but put the controller out of reach for rain and higher temperatures normally found in BB engine compartments where long tube headers are being used. Having switched to a EFI system I also keep ALL sensor wires away from ANY power wires and absolutely no wires anywhere near the Ignition wires feeding the spark plugs.
My PWM fan controller's power wires are both run to the battery but before installing them, I twisted them, wrapped then in electrical tape and then installed them. I do not have a short wire going to the chassis for the ground but instead I ran the ground wire all the way to the battery negative post. On the DeRale System with my dual SPAL fans I used a #10 wire to supply power to both of the cooling fans to ensure they never got anything less than full battery voltage.

 

Hi,
What fan/s do you control with it?

 

Ligenfelter makes a very nice variable speed fan controller.......I have personally installed this on three Resto Broncos with Coyote 5.0's
Lingenfelter VSFM-002 Variable Speed DC Brushless Fan & Pump PWM Controller

Jebby

 

Old thread but to update.... my PWM failed after just a few years. Im using a Dakota Digital duel fan controller with dual 12 inch spals..2 different on and off temps, one Dakota Digital sensor. Works great. Dual fans are much quieter than the single 16 inch Spal fan I did have

 

 

I made my own with directions I got from one of the off-road forums. I went to pick & Pull and took an anti-lock brake controller, three or four "BOSCH" relays, grabbed a diode that fits the box, some fuses, and some wire, $15.00 total. Took about four hours to configure in the box to work properly, and it hasn't failed yet. I have two 12" fans that came from some aircraft carrier sized Chrysler product, made my own aluminum shroud too. I have the temp sensor/switch mounted in the middle of the top rad. hose, and I'm running a 160 stat, It stays below 200 sitting in traffic. I mounted the sensor in the rad hose because my battery was getting drained due to fans running for so long after turning the off, when the sensor was mounted in the manifold.

 

I wanted to also provide an update about the DeRale PWM 16795.

Been running mine since 2019 and it is failing. Need to look in a new direction.

Thinking the Dakota digital. but where to put it? It is supposed to be inside the cabin.

 

I had the exact same issue...Derale PWM failed and I went to Dakota digital. I have in in the cabin behind the passenger dash pad. Works fine there.

 

When you say it's failing... What's it doing (or not doing?)
M

 

I’m also curious about the symptoms