dealrcn

Looking for a good fan control switch that will fit into the same port as the factory temp sending unit in the heads. What's everyone using?

krochus

iTrader: (1)

I researched this and researched this.

I can tell you with a pretty fair degree of confidence that there isn't one.

89gmcs15

iTrader: (7)

I am using a probe style switch in the radiator. Dual fan control and it works. Got it at oriellys fyi.

Pop N Wood

iTrader: (1)

+1

Painless makes a kit that seems to include a metric switch, but you have to buy it with a harness and relay. They don't sell just the switch. Several attempts I have made to turn down stock switches have all failed.

cruisin'73

iTrader: (8)

I was in the same boat, and here is how I solved the problem and stayed on budget. I used 2 of the adjustable temp fan controllers that 89GMC mentioned. I mounted them in a small $5 tackle box and ran the probes into the radiator inlet hose. With 1 controller for each fan I have the ability to trigger 1 fan at a "low" temp and the other at a "hi" temp. I also wired a dashboard switch so I can turn on the "hi" fan manually. So for $35 I emulated a $250 SPAL controller setup! 2500 miles of trouble free operation!

I did find out the hard way that the temp adjustment ***** on the controllers IS LIVE! I grounded one of them out to a wrench once and fried the controller. $15 done the drain... to prevent that from happening again I cut a short length of rubber hose and push it over the ***** to prevent another accidental grounding. Live and learn.

Oh, and of course I have the controllers wired to a relay for each fan. Those F-body fans can pull BIG AMPERAGE and I wasn't about to put those controllers under that kind of load.

krochus

iTrader: (1)

I wired mine with a "high temp" fan switched with the aforementioned probe style unit.

Then I wired my low temp or continuous fan off a simple oil pressure switch. Both switched via 88880045 GM fan relay & harnesses.

The fan relays are powered by the same circuit as the MSD so in theory if I loose fans I also lose ignition too.

snook

iTrader: (1)

I have the same setup as the other guys. Works fine. I just have high hooked up to my fans, could do low but I dont see the need. The small adjustments on them are finnicky so just do a little adjustment at a time

dealrcn

Ok thanks for all the info. I think I have come up with a good solution. Derale performance makes a switch #16730 with 1/8" npt threads. Use it with a M12 x 1.5 to 1/8" npt adapter fitting. The switch comes on at 180 and off at 165. They also make one that operates at 10 degrees hotter.

speedtigger

iTrader: (16)

I used a painless fan controller that operates off of the factory sensor.

Pop N Wood

iTrader: (1)

Finding one with a 1/8 npt sensor is a good find. I have a cheap harbor freight temp gauge wired into the passenger head the same way.

Derale also makes a switch with a radiator fin probe that is pretty cheap. I end up going that way due to a lack of other options and once I set the probe with JB weld putty it has worked flawlessly.

Don't know why no one makes a temp switch for the metric fittings. I would love to have a 200 some degree mechanical one like that as a back up for the high speed fan.

1981TA

iTrader: (7)

+2 on that.

I tapped the top of my water pump outlet for 1/8 NPT and ran the temp sensor for my VDO gauge from there.

JGS

Did pretty much the same trick but for my '02 truck. Got me a step drill bit (don't go past 9/16") and a 3/8" npt tap (via Harbor Freight) and tapped the top side of the water pump. Make sure to suck the burrs out of the pump. Hope you can see the pic.