90 da overheating

my car over heated yesterday and i realized the fan wasnt on, it cooled off while i was driving. my question is which sensor can i jump to make the fan come on with the ignition until i figure it out, i jumped the back one but the fan came on constantly even with the ignition off

It’s a sensor with two little prongs sticking out of it on the back of he block under the manifold. Mine is jumped and only turns on with the ignition.

I am having this same problem. There are a few threads on this out there which are helpful. There is a sticky by Collins also that breaks in down: It tells you the name of sensor, location and color wires. I have a B20 engine, I have check it out and it seems that I have a cooling fan switch and oil pressure switch on the back of block and on the side of the side of head…Can anyone help on this one? I am stumped on which to jump or probe…
http://forums.g2ic.com/showthread.php?196564-Engine-Coolant-amp-Oil-Temp-amp-Pressure-Swiches-Sensors-amp-Sending-Units-Explained

http://forums.g2ic.com/showthread.php?196564-Engine-Coolant-amp-Oil-Temp-amp-Pressure-Swiches-Sensors-amp-Sending-Units-Explained