View Full Version : engine fan won't turn on

05-26-2004, 04:26 PM
Just joined this site today so bear with me, my engine fan won't turn on unless i turn my windshield defroster on inside my car, i own a 93 thunderbird sc and it makes temperature rise slightly higer than norm so i run defroster on low at all times to keep engine cool but i want to fix this problem.
thanks for any support.

05-26-2004, 04:31 PM
you know were the AIR BOX is, in fron there is this lil computer, unbolt that, it has all the wires numbered, look for the NUMBER 14 wire and cut it, now when u turn on ur car ur fan turns on automatically, if u want u can wire a relay to break ciruit and turn the fan on, pretty much like a AUTO or ON switch, if the ciruit is CLOSED its on AUTO, if its OPEN then its in the ON position, your choice,

05-26-2004, 04:33 PM
sweet, thanks, i'll try that, hope engine light doesn't go on though.

05-26-2004, 04:39 PM
Thats good info, but whats the right way to fix this?

05-26-2004, 06:10 PM
the TEMP SENDING UNITS are dead, my fan never turned on, i ran a code tester and got TEMPERATURE SENDING UNIT OUT OF RANGE, need to replace that, probably thats why, if they die they dont give a CHECK ENGINE light,

dont worry the CHECK ENGINE light doesnt turn on if u cut the wire

05-26-2004, 10:28 PM
There are two temp sensors. One on the front drivers side of the blower, and one on the passenger side more towards the back. The one on the passenger side is the one that gives input to the EEC and the engine fan. The other is what runs the gauge on the dash.

Usually if that sender goes bad you get pretty bad fuel mileage as well as the EEC runs things a bit richer when the engine is cold. The EEC will think the engine is always cold.

By turning on the defrost it kicks on the A/C. When the A/C turns on the coolant fan is supposed to automatically turn on. That it does that for you is a good sign that the fan motor is good, and that the relay module is likely o.k. as well. So focus first on the signal for coolant temp maybe being bad.