Derale 16789 High Amperage Dual Fan Controller with 3/8" NPT Thread In Probe

First, I want to say that I was very skeptical buying this fan controller as there’s a decent amount of bad reviews. I emailed Derale to ask what was up with the controller, if there’s any known issues and they re assured me those bad reviews are from people who either mis-wired the controller or used improper fans. So, I ordered it. I wired everything this past weekend and let the Jeep get up to temp, fans didn’t turn on, instantly regretting my decision I broke out the multi meter to double check my connections, all was good. I ended up having to turn the adjustment screw counterclockwise 8 turns or so for the fans to operate and now everything seems to be working as it should. First fan kicks on and the second follows as the coolant temp gets hotter, I’m not using the over ride function.

I returned one, tossed one, and used one. Let me just say, there’s issues with the operations in manufacturing process otherwise a good design but poor execution. Just ask the people who work at Derale. If their honest, the’ll tell you about how these units have many problems. Sorry to say, Derale makes some great products, this is not one of them.

No problems put on monster fans works great after 6 months still works great

I found the product well-made but it’s not waterproof you need to mount it in a location where it won’t get wet The other problem I found is the override or AC switch only turns on one fan where is my application I wanted both fans to turn on with the override the switch is mounted and an 83 jeep that climbs rocks and I need the cooling fans on at hi RPMs and low-speed the fan comes on automatically but I would’ve preferred a complete override

I upgraded this from Derale's 16720 single stage fan controller that was giving me issues. The 16720 claimed it was for 25AMPS, but I have melted fuse housings and relay wiring that suggests otherwise. I digress.The 16789 gives me confidence. By factory settings, the first fan obediently turns on at 200F and off at 180F. I am not even sure the second fan has even kicked in once yet since the first fan always keeps things under control. For this reason I do like how Derale staggers the dual fans on/off. I am much happier with this vs. factory fans that kick on around 235F. This keeps it right at the thermostat's full open position while keeping the engine nice and cool.As you can see, the case is heavy duty with heavy duty wiring connections. There is nothing light duty about it including the big circuit breaker. it looks and feels like a factory fan controller. My only feedback would probably be I would like connectors for the temp sensor leads so I could have unplugged the temp sensor and routed the wiring by itself instead of having the temp sensor pre-wired to the box.Note that the temp sensor does have 3/8" NPT threads, so it's pretty beefy and you will need somewhere to put it. For some reason, I assumed 1/4 or 1/8 NPT threads and had to custom drill/tap a thermostat housing for the big 3/8" body.I have about $8k into a brand new motor, and this controller makes me comfortable that the fans are under control.Edit: 5 stars to 1 star. On hot days this piece of crap thermally trips and the fans don't work until the engine compartment cools down. This unit can't be trusted. I can't mount the controller any farther away from my engine or radiator. Also the leads on the coolant sensor pull out of the potting material. The strain relief is poor.

Good tech support too when I miss understood the directions. Emailed them and they got right back to me

Works great. No issues with the thermostat cutting on the fan or the air conditioner override. Both work great.

YES I DID SHOUDED LAST MORE THAN LESS YEAR