cooling fan issue

[cobrasan]

Searched and found nothing like this:

car overheats on me yesterday and I notice the fan is not coming on low or

high after I maxed a/c. Wired the fan to the batt and it runs fine all the way

home.

This morning I checked all related fuses including PCM fuses. Checked the relays.

checked the plugs at the fan and nothing unusual. Start the car today and

put the a/c on max fan comes on. ok. so I shut it off restart the car with a/c

off and at its usual temp the low fan comes on. Then after a minute or so it

shuts off never to start again. Even placing the A/C on would not engage fan

and the car got hot again as expected. I am leaning towards the PCM being the issue although no codes where thrown.

any advise is appreciated.

 

[sportinawoody]

there is a relay on the fan shroud. look around the base at the wires for burnt, cooked wiring. if you have a meter and tuner, watch tuner for fan command until fans dont come on when commanded and check for signal at the relay and of course,,, b voltage and ground. also the temp sensor is under the intake on pass. head, you can try jumping that .

 

[cobrasan]

checked the sensor to see if its reading temp correctly and it is. as far as it signaling ill work on that however i thought turning the ac all the way up would bypass that and it did not. I have an xcal 2 but I don't think it reads when the fan on signal engages ill double check.
when I wired the fan directly to the battery I did so through that resistor and it functioned properly.

 

[sportinawoody]

that resistor about cost me my motor twice. the 1st time the wires burnt in2. the 2nd just crapped out but i believe the 1st one done all the damage. story being, later down the road i had the relay box apart for another reason and found the terminls literally burnt when i seperated the box. you can try inspecting there but you will have to seperate it and look for burnt/black pins. dunno if my resistor caused this or this burnt my resistor up but its fixed so thats all that matters to me

 

[wht67]

Check your fan power connector. I had intermittent fan turning off and causing overheating:

Searched and found nothing like this:

car overheats on me yesterday and I notice the fan is not coming on low or

high after I maxed a/c. Wired the fan to the batt and it runs fine all the way

home.

This morning I checked all related fuses including PCM fuses. Checked the relays.

checked the plugs at the fan and nothing unusual. Start the car today and

put the a/c on max fan comes on. ok. so I shut it off restart the car with a/c

off and at its usual temp the low fan comes on. Then after a minute or so it

shuts off never to start again. Even placing the A/C on would not engage fan

and the car got hot again as expected. I am leaning towards the PCM being the issue although no codes where thrown.

any advise is appreciated.

 

[cobrasan]

fan connector looked good. the resistor on the shroud I opened it up and checked inside seemed ok. Sportinawoody did you open up the power distribution box and find the issue their? ill get out and look.

 

[cavero]

I just had a similar experience yesterday:

-I'm stuck in stop & go traffic for 10 min, with max A/C on.
- Noticed the A/C wasn't cold anymore and saw vapor escaping from the corner of my hood. I kick on the heat full blast
still stuck in traffic for another 10 mins and then the engine gets so hot it trips fail safe mode and throws this code:
P1299: Cylinder Head Temperature Sensor Detected Engine Overheating Condition

-as I'm about to get to a place I can pull over, I finally remember I have a bluetooth OBDII adapter and torque, so I pull up the coolant temp and its ~239 deg.
--I pop open the hood and see the coolant is boiling and the fan is off.
--I shut off the car and let it cool off for a couple minutes with the heat on full and then restart it so Torque will tell me how hot the car still is. Still no fan. Shut off the car while I looked up the fuses.
--I pulled the 40A fuse from the high power junction box and everything looked in tact and clean.
--put the fuse back in and start up the car. Fan comes to a full roar.

--after another 5 min of running with the fan on, the temp comes down to the point where the temp gauge moves back down to the center (I'm drawing a blankbut think it was 220) and I very carefully drove home, though every time I started moving over 10 mph, the temp climbed back up 5 to 10 degrees.

The only thing out of the norm was I was on day 4 or 5 of running a fuel system cleaner (BG 44K), which I think burns hotter than untreated fuel based on what a Google search would tell me. When the car finally cooled back down, I put 1 gallon of coolant in and filled up my tank with 12 gal to dilute whatever fuel cleaner was left. My drive to work, and home, was uneventful. the low speed fan kicked on at 195 deg and I never went higher than 197. I wasn't stuck in traffic for more than 5 min though and never turned the A/C on full blast

 

[cavero]

I forgot to ask: does anyone know the PIDs for the HIGH_SPEED_FAN_COMMANDED and LOW_SPEED_FAN_COMMANDED? I log them with SCT live link, but I'm not taking my laptop everywhere I go. I want to put them in Torque.

 

[cavero]

I ran across this trouble shooting thread, looks like may be exactly what we're looking for
http://www.allfordmustangs.com/forums/2005-2010-mustang-gt-tech/284062-cooling-fan-testing.html

 

[sportinawoody]

Check your fan power connector. I had intermittent fan turning off and causing overheating:

i think you might want to pull the lid off your junction box and look for burnt pins judging by that pic. my opinion is the fan was set too low to come on and ran constantly causing it to overheat the circuit . i since set my fan temps to 185/ 190 to allow the fan to cycle off with my 170 thermostat and never had a problem since

 

[sportinawoody]

or just get a standalone fan controller

 

[avinaj80]

I had this same issue. Came to the conclusion that the plug had corrosion. Got some electrical connector cleaner and some dialectic grease on the plug, haven't had an issue since.