05-27-2008, 06:39 PM
Yep digging this thread up.
Going through the electric fan thing now too.
If you want a simple setup this is what we do.
Get a temperature switch from someplace like a HD truck parts place, I got this one from a freightliner dealer.
Part number 8039032P $28 single post, normally open. Closes at 200 degrees, ground through case, opens at 10 degree differential.
or
Part number 803034P $30 single post, normally open, closes at 210 degrees, grounds through case, opens at 10 degree differential.
So screw that into a water jacket on the engine, hook the ground wire from the relay up to it.
It will come on when desired 200 degrees is reached, and opens, or shuts fan off when it reaches 190.
Every engine is different the way the water flows. For many engines a 200 degree switch will never cool down enough to shut the fan off if placed in the back of the block or the head, but if in the water neck it will work perfectly.
For the back of the block or in the head I usually use the 210 degree.
Power can be wired from the battery which will run the fan with key off, but is kind of silly because the pump isn't turning to circulate water.
Or key switch it.
Boom fully automatic for $30.
Those part numbers are out of an MEI catalog which is typically repackaged with the dealers name on it.
They have pages of temperature switches. If you want to get fancy with a dual function for running two fans, or two speeds they have switches for that.
Just don't fall for the $200 fan control mystery box.
Going through the electric fan thing now too.
If you want a simple setup this is what we do.
Get a temperature switch from someplace like a HD truck parts place, I got this one from a freightliner dealer.
Part number 8039032P $28 single post, normally open. Closes at 200 degrees, ground through case, opens at 10 degree differential.
or
Part number 803034P $30 single post, normally open, closes at 210 degrees, grounds through case, opens at 10 degree differential.
So screw that into a water jacket on the engine, hook the ground wire from the relay up to it.
It will come on when desired 200 degrees is reached, and opens, or shuts fan off when it reaches 190.
Every engine is different the way the water flows. For many engines a 200 degree switch will never cool down enough to shut the fan off if placed in the back of the block or the head, but if in the water neck it will work perfectly.
For the back of the block or in the head I usually use the 210 degree.
Power can be wired from the battery which will run the fan with key off, but is kind of silly because the pump isn't turning to circulate water.
Or key switch it.
Boom fully automatic for $30.
Those part numbers are out of an MEI catalog which is typically repackaged with the dealers name on it.
They have pages of temperature switches. If you want to get fancy with a dual function for running two fans, or two speeds they have switches for that.
Just don't fall for the $200 fan control mystery box.