I can probably use a different controller. Amperage rating for the dual 13.5" fans is 16A - 28A although it is an inductive load so the start-up spike is likley twice that upper limit. Their controller stutter-starts the fans to limit start-up spikes. The flex-a-lite controller modulates the power from 60% to 100% dependent upon the tempreture set points. It also allows the fan to run for 30-45 seconds after engine shuts down. It already monitors the AC and runs when the compressor is on. I have a a cab-mounted OFF switch. I did check their site yesterday to see that may have updated the design. I am going to call them for their 2 cents but it maybe time to try something different like DCC or SPAL. I'll report back when I figure this out. Thankfully I have a few months before the truck will be needed as my winter commuter. Thanks for all the help. Brew <img src="/forums/images/graemlins/cheers.gif" alt="" />

Brew,
Funny thing... I still have your old fan/clutch assembly. I've kept it as a spare... JIC. If you want it back it is all yours. I don't have the shroud though...

Joel

Thanks Joel!
However David at Flex-a-lite has convinced me to try them one more time. He tells me they've done a redesign on this controller (3rd times a charm)and that he hasn't seen one of the new ones come back yet. They pulled some of the heat generating work off of a single MOSFET and spread that load as well as got rid of the spade style connectors for factory soldered wires that get spliced downstream from the controller. The failing components were always near these connectors so it does make sense. So I'm going to give it another try since I don't have to depend on this ride as a daily commuter but damn this has been a rough road. <img src="/forums/images/graemlins/scared.gif" alt="" /> Brew

I guessed they were using MOSFETS, which frequently die when used in car fan speed controls.

Hopefully there is a heatsink on the thing. You can help it last longer by mounting it where air will blow across it.

FETs sometimes fail by shorting (fan will go all the time.)

If it does die again you can replace with a higher rating if you can get the heat away. The cost difference is about ten cents, nothing from your point of view, but that's quite a bit for a truckload of devices.