Not really sure what the best section to ask this is lol but let's give this a shot.

I swapped Dodge Intrepid fans into my 04 4.3l and they cool AMAZINGLY well; low speed is PLENTY, even at idle and with the AC on just sitting in the hot Florida sun. Right now they're wired for one speed circuit to kick on when the AC is turned on (via splicing into the clutch 12+), and the other low speed circuit to kick on when the engine warms up (via a temp switch in the passenger head).

The AC kick on circuit isn't what's giving me issues, that's actually the simple one; throw a relay when the AC compressor clutch engages, viola, 12+ on the business prong of the relay.

It's the temp controlled circuit that's giving me headaches... I've had issues in the past wiring up temp controllers that use the probe stuck into the radiator core. They don't seem to last... So instead this time, I stuck a simple temp switch in the spot that the plug is in on the passenger head (the spot where the temp sensor is on the driver's side head). Acts as a ground interrupt in the circuit. When it works like it should, it works great; the engine get's up to temp, the fans hold off until I come to a stop and idle for a bit, like in traffic, then once the engine heats up a little, the temp switch clicks, throws the relay, the fans come on, cools down the engine (fast I might add), and within a minute the engine drops 20 degrees and shuts the relay and fans off, just like it all should work.

My issue is, I can't find a dang temp switch that'll last! I've put two in the truck within the last 6 months because they keep failing... And I know it's the switch because I can take the lead going to the switch (just a single wire), ground it out on anything, the relay trips and the fans kick on, so the wiring circuit isn't the issue...

So what is everyone doing for fan control by engine temp? Preferably something that doesn't involve a $150 control box... Temp adjustability isn't a big deal, I have no adjustment over the temp now just using the switch in the side of the head (which if I recall correctly is suppose to kick on at 215).

I figured this super simple circuit, using the temp switch as a ground interrupt the trip the relay for the fans (note the switch is NOT carrying the load of the fan, it's just tripping the relay) would be a simple, inexpensive, and reliable way to control the fans, but I'm beginning to think otherwise... I'm almost one more failed switch away from just wiring one speed to always be on with the ignition

 

I wish i could help you but i don't know. However that is a good looking setup you have.

 

i've bought all my sensors out of summit and had no problem with them - they hold up well

 

I have an adj I mounted on my fan shroud hooking the low speed up to that and hooked up a toggle for the high speed

 

thanks the goal was to have the fans blend in and have them look pretty much factory



that was my next step, try a switch from a different source, a difference brand. wouldn't mind going with one that kicks on at a little lower temperature too... the one that's in it now is from O'reilly auto parts, can't think of the brand. current one is going on two weeks and still working :P



I've actually acquired from work an adjustable one that uses a probe in the radiator core. I'm not too fond of them, but if the temp sensor keeps failing me I might just give it a try...

 

what i like about the adj. is I have it set to come on earlier, around 180 degrees. and its direct wired so it will stay on with the key off till every things cool. Heat is the killer of engines. 2 years without a problem

 

yeah mine's direct wired right now too, ign does not have to be on for it too kick on, so when I park the truck and the engine starts to heat up when I shut it off, the fans will kick on after about a minute and continue to run for about 5 minutes after I leave the truck.