Cooling Fan Issues

[DHMag]

2 days ago, the fan worked. as i pulled into a steep drive, the face of the bumper smacked the pavement. that was the last time i recall the fan working.

yesterday, upper radiator hose developed a leak. replaced hose, flushed system, added new thermostat, added new coolant, fan does not operate.

i unplugged the fan and wired it directly to the battery, it is operational.

with EATC off, temp reached 230* and fan never came on.

with EATC set to Max A/C, fan still doesnt come on.

with A/C low pressure switch unplugged and jumpered, the fan works.

there are no other issues with the car. at first i was thinking IRCM, but now im thinking A/C switch.

any ideas ?

TIA

 

[NEILL93SHO]

mine did not come on until i noticed it was running rich too, and replaced the ECT sensor. Now it comes on any time the needle goes above M.

 

[SHOZ123]

The fan is controlled through two circuits in the CCRM (IRCM), low speed and high speed.

The low speed is from the ECT only and should turn on when the temp reaches 215F, it will cycle off at 210F.

High speed is turned on when the A/C compressor is in an active mode or through the ECT when the coolant temp reaches 230F, off (to low speed) at 224F.

The fan will not run at speeds above 48 mph.

So.. if the fan does not work when the key is in run (engine off) and the A/C compressor mode is active (defrost, normal A/C, max A/C or floor/vent) they high speed circuit is dead.

If the fan does not come on when the temp exceeds 216F the low speed circuit is dead.

If both circuits are dead then chances are there is a ground issue or the fan itself is bad. Test the ground wire on the fan plug with an ohm meter for resistance to the neg battery terminal, should be ~1 ohm.

Try pulling the fan plug off and grounding the ground terminal on the fan while applying 12V to either of the other two terminals. Be careful of the fingers and use big wire as there is going to be 15A or so pulled. If the fan moves then the problem is probably in the CCRM (ICRM).

The relays in the CCRM are turned on by the PCM sending 12V+ to the correct relay coil. The relays should have 12V+ at all times the key is in run to the switched power contacts of the relay and the coil ground should be constant.

 

[DHMag]

thanks for the input Paul.

as for the 230* temp reading: in the past, when the temp guage on the dash reached an indicated 220*, the fan would come on. fan would shut off at 210*.

as i stated, by wiring the fan directly to the battery, the fan works. (mind you, this is a Gen1...only 2 terminals in the connector).

according to what youve stated against what im actually experiencing, i have lost a ground somewhere. i know the fan isnt bad.

right now, the A/C pressure switch is disconnected from the accumulator and a jumper wire is attached to the connector, making my fan operate all the time.

maybe the loss of ground is a result of the bumper face smacking the asphalt. ill look into after i get the 'Bu home.

thanks again Paul

 

[SHOZ123]

Be sure there is 12V on the brown/orange wire going to the IRCM.

 

[rlw001]

Excellent info! Thanks Paul!