Hayden 3651 Universal Add-On Adjustable Thermostatic Fan Control Kit, Custom Fitting & Wiring Required

They worked pretty good the time they lasted. Purchased two and installed at the same time. One died in four months and the other died in 6 months. I ran one to one radiator fan and one to the other radiator fan. Since radiator fans are known upon startup to draw 30+ amps. I used two as a precautionary measure. One fan pulled 25 amps and the other pulled 20 amps. Maybe mounting them anywhere other than under the hood would anyone in the future. They do get extremely hot no matter where they’re mounted. Even ran shotky diodes near the fuse holder in the circuit as triple precautionary measure. Fans are okay. I rate them two stars because when they worked they worked good. I am no amateur or novice at any kind of wiring. So I definitely know what I’m doing. Will be wiring a digital fan controller and relay for half the price.

First off i am an electrician. So wiring is easier to me than most. That being said. I did not run my fan threw this unit as in the instructions. I dont belive this unit is capable of running dual fans. I instead used the fan out put signal to trigger a 50 amp rated relay that controls my fan. My fan is a performance fan from Derale so it has a sustained 25 amp draw while in use. I like the variable setting that allows you to triger the fan at what you desire. Right out of the box it triggered at 160 degree which is to low for my taste. I let the coolant get up to 182 degrees and adjusted the blue dial until the fan triggered. After that the fans turned off at about 10-12 degrees below the 182 temp. If you rather the fan stay on all time just adjust trigger to below the cooling capacity of your car. My car can cool the coolant down to 170. Another great feature is the AC FAN TRIGGER feature. When the ac signal is present at the compressor you tap that signal to the green AC wire. When your ac is turned on it will automaticaly trigger the fan to come on. I also like the fact that the temp probe is plumbed into the coolant system vs dry contact in between the radiator fins. In all great little controller. AGAIN I DO NOT RECOMMEND RUNNING YOUR FANS THRU THIS UNIT. INSTEAD GET A EXTERNAL RELAY AND USE THIS TO TRIGGER THAT RELAY.

The installation was painless and very easy. However, once it was installed was when things went awry. from the moment that the key was turned on--the relay in the controller chattered away. It did what it was supposed to do--keeping the coolant cool and all that, but clickety clicked away. After about a week, the behavior became erratic and the controller would either turn the fan on forever (even if the vehicle was off and it was below 40 degrees outside) or it wouldn't come on. Thats when i pulled it out and chocked it up to being a defective unit. Since I still had the wiring all setup for that particular controller, I installed an identical unit. Then, pretty much the same story all over again. I checked my connections, checked the relay itself, even measured the voltage coming OUT of the unit. when the relay chattered, i read voltage approximately 2.5 or 3.5 vdc--when it should've been 12vdc. Needless to say, i'm ripping out this one and getting something different.

The probe I received was much bigger, threaded, and likely meant for a specific petcock or adapter to install in the block. I was able to work it into the fins securely enough as that was my only option. So far this works wonderfully when wired correctly. The wires to the fuses are pretty loose so a little epoxy was added. With a secure ground and an extra relay if you want another fan you should have no issues. AC switch and temp adjustment works as advertised.

install was easy and the unit works great only thing is instructions say to set it when the thermostat opens and it will be set properly the problem is if you set it when the thermostat opens then once you are warmed up the thing never turns off then you fave fans running non stop you have to set it to a comfortable temp that isn't overheating but about where you would be sitting at a red light for a little to long I set mine 15* over the thermostat the fans only come on if I am in stop and go traffic or sitting to long and go off after driving a few min and stay off while I am driving I never get close to overheating and the fans don't run to much

These things work well for about 6 months to a year, then the contacts in the controller go out and you no longer have a cooling fan. I have a manual switch online just in case but I've seen times that even the manual switch didn't turn them on. I'm on my third controller presently and I know the rebuttal, but it's easier for me to replace the unit than change the whole system. Just wish they upped the contacts to a heavier rating. And by the way I'm not talking about the relay that is in the unit, it seems to be heavy enough to handle my two fans. One is main cooling the other is a/c fan.

While I only have had installed for a week so far so good, takes a little bit of time getting the ON temp set correctly but once it's set it's Good to go. I placed the temp sending unit into the upper rad hose via a nifty little hose splice with 1/8 NPT hole and thread already pre drilled. Time will tell how long it lasts, I will update if and when problems arise. * update 9/21/19 Well the relay started not working with out me holding pushed in place, I'm going to say it lasted 2 yrs without any issue but have to knock a star or 2 off because really feel like it should have lasted a bit longer than that. Going to search options, may or may not buy another one.

I have bought several of these controllers over the years and i found that the controller cant handle the power draw of the electric fans that use however to get around the controller failing in a few months i used a second relay and separate 30 amp maxi fuse that can handle the power draw and help make the controller last longer. after doing this ive been running same controller going on 8 years now with no problems