Installing an aftermarket cooling fan switch?

[takza]

I'm testing a hot air intake for mpg gains and found that this causes the engine cooling fan to run too often in warmer weather...reducing potential gas mileage.

So I bought a $19 adjustable mechanical fan switch from Autozone (also JCWhitney).

This switch is rated for 15 amps...whereas the cooling fan draws 6-7 amps...so no relay is required.

I mounted the switch on the pass side shock tower...ran the capillary tube down to the same area where the OEM sensor is.

I made up a holder for the bulb by wrapping some heavy copper wire around it 5/6 times and left two prongs that I pushed under the fins of the rad...allowing the bulb to lay on the "shelf" right above the bottom of the radiator.

The capillary tube is FRAGILE.

I have this wired/fused directly to the battery (should be using ignition switch current?).

I had an spare fan with an extra connector...so I used this to connect to the fan right behind the grill. So if and when I remove this switch...I can just plug in the old control circuit and it's ready to go.

Working just fine so far. Have the switch adjusted so the fan never runs unless the coolant temp gauge reads over 1/2 on the gauge...shouldn't run at all unless idling off road in hot weather.

Also have an indicator light under the dash that lets me know if the fan runs.

Anyone having mpg issues might want to install a light to see if their fan is running too much. Not sure what Toyota wants for a new fan switch...but it's probably near the $20 I spent.

[takza]

Ended up putting the temp sensing bulb INSIDE the top rad hose right near the sensing units for the temp gauge using some gasket goop and tightening the hose down on the capillary tube.

Now getting good control over the fan.

Also tied into the ignition switch to avoid having the fan run after shutdown.

Fan does not run unless caught in traffic on a hot day or idling offroad.


Need to remove the bulb from the rad hose, clean it, and cover it with a layer of silicone gasket goop...think there might be a tendency for the bulb to eventually corrode.

This switch works real well...I also have a fan indicator light that goes on when the fan runs.

[gmeddy]

i have these two plugs that are not hooked up to anything over on the battery side of the front end, i thought the round one may be another thermo switch line for a second fan.
and the other one down lower towards where my finger is pointing, has 6 wires, where would that go?

any ideas?

[takza]

Recently replaced the top rad hose and the sensor bulb was in new condition...no apparent corrosion...switch still works well.

[splatterdog]

Well it's been two and a half years. What have we learned from your experiment? Besides your engine runs hot now.

[takza]

Well it's been two and a half years. What have we learned from your experiment? Besides your engine runs hot now.

Still works just fine...only use the "hot" air setup in winter. In summer...the fan only runs when idling offroad...or after parking and restarting. Fan runs when the temp gauge gets slightly above 1/2 way.