fan wont turn off...

[chickenandpickles]

my 87 b2200 engine fan will never turn off....it runs constantly....the fan switch that is in the bottom of the rad "was" broken off so obviously i figured that was the only problem...after changing it, and plugging the 2 end to it, the fan is still running constantly, it never kicks out...what else could be causing this? please respond...

[89B2200]

I thought mazda b-series trucks only have clutch fans??????
Did you convert it to electric fan? Just wondering.

[mazdatech]

I am wondering the same thing 89b2200 .......87b2200 first year of the 2.2......

[chickenandpickles]

i never converted anything i bought it the way it is a few years ago...hmm....its the big engine fan on the rad...i was looking for a way to stop it from running but cant figure it out....the only way the fan can move is from the switch sensor with the 2 prongs(which was broke and i changed) the only other way it can spin is from the belt that also goes around the alternator, i dont see any other electrical connections to it. when the truck is running I touch the connections to the switch and i do hear some clicking from the little sensors up by the wiper motor...

[chickenandpickles]

it is not an electric fan...something is telling the fan motor to stay on...is it the coolant temp sensor? where can i find it? i see there is a small sensor with a wire connected to it just beside the thermostat, is that it? what else could make the fan motor stay running?

[89B2200]

Mazda B-series Cooling system 101:

Radiator fan is thermal-fluid clutch coupled.
Clutch is driven by a v-belt thru the crankshaft and alternator pulley
When engine is cold, the clutch fluid is cold and the clutch slips so the fan blades free wheel so minimum drag on the motor.
When engine gets up to temperature, the clutch fluid heats up and drives the clutch as well as the fan blades forcing air thru the radiator.

There is no switch that activates the clutch fan! It is thermally activated.

Hope this helps.

[mazdatech]

i once had a bad fan clutch. In the morning on cold startup the fan clutch would lock up and sound like an aircraft taking off. Then it would return to normal operation and work fine.

[chickenandpickles]

i just replaced the coolant temp. sensor....started the truck up.... and the fan is still always on......im going to change the thermostat later....can someone tell me where i can find the computer for my truck?

[89B2200]

Maybe the previous owner installed an electric radiator fan to replace the clutch fan to get some more power from the trucks weak motor.

Maybe you need to shoot and post some pics of the install and we'll see.

[mazdatech]

Good idea, post some pics for us to look at.