Join Date: Sep 1999
Location: Tampa Bay area, FL
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Easy Adjustable Thermostat install...
As I'm sure most of you know, the stock cooling system has a thermostat in the lower radiator hose that is supposed to trigger the aux. fan when the temperature reaches 210*. Of course, the lower hose is the coolest part of the entire system, so if that ever reached 210* your engine is already fried.
There are two wires that run to this thermostat. Power is fed into one wire, and when the temperature is high enough, a circuit closes and the power flows out of the other wire to a relay, which then triggers the aux. fan.
I used the aftermarket adjustable thermostat made by Hayden Automotive. Part # 226203 (Also has "Imperial Automotive Products on the package). I bought it at AutoZone (I think), and their Part # is 1222.
It consists of a probe that is "zip-tied" behind the radiator and is attached to a small control box via a fairly long wire. This small control box has a bracket to mount it to the inner fender, and two small spades for plugging in the Power and Signal wires.
I removed the air box so I could drill a few holes and mount the control box to the front end of the inner fender.
I removed the aux. fan and grill, then mounted the probe to the radiator, running it's wire so it can be taped to the stock aux. fan wiring harness.
I cut the wires to the original thermostat. I cut them as close to the thermostat as possible, and crimped on the female spade connectors from the kit.
After reinstalling the fan and grill, making sure the wires were routed correctly, and using a test-light to find out which spade-connector had power (only with engine running), I hooked the spade connectors up to the control box. (I mounted the control box so it was at the top of the bracket, with the spades facing the rear of the engine bay. In this position the power wire is the lower spade and the signal wire is the upper.)
I started the engine and brought it up to temp (~190*), then set the new thermostat to come on at that temperature by slowly turning the adjustment screw clockwise.
I unplugged the signal wire and ran the engine up to 210*. Then I plugged the signal wire back in, the aux. fan kicked on, and I sat in the cab and watched the temperature come back below 190*. The aux. fan kicked off automatically and I danced a little jig. [img]images/graemlins/grin.gif[/img]
After 3 years, I can finally run my truck hard and it won't hit 210 degrees! No more turning on the AC and sliding the temp to the hottest setting to get the engine cooled off in traffic [img]images/graemlins/crazy.gif[/img]