I read some where in the BB forums about how a person had trouble troubleshooting his air cooling fan and cant remember where it was because i was to stupid to book mark it . if you know of it or another source of troubleshoot fans on foremans be much appreciated.

It goes into detail as what to look for and how to test each componet.

thanks

 

I have a service manual, and its pretty lengthy.
Whats the symtoms?
oil warning indicator wont go off?
oil warning light wont come on, when oil is over the specified temp?
cooling fan motor wont come on,when oil is over the specified temp?
cooling fan motor wont stop?
What year foreman?
Will the fan work, when 12 volts is applied, directly to the fan?

 

HB

I applied +12 to the fan directly and it is fine

I checked my oil last week end and was down almost a quart (Yikes) I suspected it as I started to hear a very slight tapping. filled oil and noise went away.

I never got an oil lite and the fan never comes on never.

I would think that being down a QT it would as the oil temp would rise and possible start to cook the oil working twice as hard.

so im inclined to believe i either have a bad fan control unit / thermostat
or a bad oil sensor as im told the sensors controls the FCU but have no diagram to chase it out with.

thank for your assistance .

 

Youre gonna need a way, to acurately check the oil temp.
Its possible, the oil isnt getting hot enough to tigger the fan. Ive never seen the light come on , on mine.
Anyway, youve already proved the fan works. Which is the first step, in the troubleshooting tree.
Remove the front fender. Disconnect the cooling fan control unit connectors, and check for corroded terminals and loose contact. There is a 4pin connector and a 2pin connector.

Next step, is to disconnect the cooling fan control unit, 2p connector. Check for resistance between the light blue wire terminal, and ground, on the wire harness side. At 77degrees F, it should be 10K ohms. Resistance will be lower, at high engine temps.
If abnormal..
Check for poor contact of related terminals.
Open circuit in Light Blue or blue wire.
Check oil sensor.

if normal..
disconnect cooling fan control unit 4p connector.Check voltage between the black/brown wire terminal, and ground of the wire harness side, with the ignition switch on.
If abnormal..
Loose or poor contact of related terminal.
Open circuit in black/brown wire.

If battery voltage
Disconnect the cooling fan control unit 2p connector.
check the voltage between the pink wire terminal and ground of the wire harness side, with the ignition switch on.
If abnormal..
Loose or poor contact of related terminal.
Open circuit in pink wire.


if battery voltage
Disconnect the cooling fan control unit 4p connector. Turn off key. Check for continuity, between the body ground and green of the wire harness side.
continuity...faulty cooling fan control unit.
no continuity...open circuit in ground wire.


to check the oil thermosensor.
Disconnect the wire from the thermosensor switch, remove engine guard. drain engine oil. Remove the sensor from the rear crankcase.
Suspend the oil sensor, in heated engine oil, to check. Dont let the sensor or the thermometer, touch the pan, or false readings will result. Connect ohmeter probes across the terminals of the sensor and measure the resistance. Replace the sensor if the readings are out of the ranges.
At 302F,150C, the resistance should be 306-340 ohms.
At 338F,170C, the resistance should be 209-231 ohms.
When you put the sensor back on, the torque is 13 foot lbs.

Let me know if you need more info.

 

HB

I took off the two connectors on the FCU the connections were tight and clean,

I measures the resistance on the Light blue wire on the 2P connector and it is open no resistance at all
on every scale of the meter.

im gathering it is leading me to the oil sensor or a cut light blue wire ???


BB

 

Or did I catch my own mistake by pulling off both connectors

as your instructions do say

"Next step, is to disconnect the cooling fan control unit, 2p connector. Check for resistance between the light blue wire terminal, and ground, on the wire harness side. At 77degrees F, it should be 10K ohms. Resistance will be lower, at high engine temps.
If abnormal..
Check for poor contact of related terminals.
Open circuit in Light Blue or blue wire.
Check oil sensor.

 

That light blue wire goes directly to the thermo sensor, without passing thru any other connectors.. So there appears to be two possiblities. Check continuity, from that 2p connector, light blue wire, to the light blue wire on the thermo sensor, (disconnected from the thermo sensor). If the wire checks ok, then its the thermo sensor. Check to see if the wire connector is loose or corroded, at the thermo sensor, then ohm check the terminal on the thermo sensor to ground.(it should be the same 10K ohm), if not, its bad.

 

ok gonna do it this afternoon.

I will let you know .

thank you

 

didnt get to it yet but im planning on it real soon

 

HB

I check the light blue wire to the oil sensor, it is in a black connector that appears to be hard wired in to the oil sensor (or stuck like heck)

How would I check this wire out with out having to cut it . because cutting it still only proves to the end of the wire and not all the way thru the connector to the sensor