Cooling fan wont come on when car reaches operating temp

Cooling fan switch ?????? Has a engine coolant temp. sensor , That inputs info to the PCM/ECM - engine computer ! The PCM / ECM interpits the voltage signal from software programmed into it as to what temp . of the coolant is . When the engine coolant temp. reaches
The PCM commands the low-speed fans ON under the following conditions:
• The engine coolant temperature exceeds approximately 106°C (223°F).
• The transmission fluid temperature exceeds 150°C (302°F).
• The A/C pressure reaches 199 psi (1372 kPa).
The cooling fans will switch from low to OFF when the coolant temperature drops below 102°C (216°F).
The PCM commands the high-speed fans ON under the following conditions:
• The engine coolant temperature reaches 112°C (234°F).
• The transmission fluid temperature is more than 151°C (304°F).
• The A/C pressure reaches 260 psi (1792 kPa).
• Certain DTCs are set.
The cooling fans will switch from high to low, except when DTCs are set, when the coolant temperature drops below 106°C (223°F).

The PCM turns on the cooling fans by energizing three different relay's .
Watch this video
Relay Driven Dual Cooling Fan Diagnostics

A pontiac montana ? There are three relay's that control your cooling fans ! unplug what sensor ? The engine coolant temp. sensor is an input to the PCM - engine computer . When temp. reaches 213 degrees the PCM energizes the relays , depending on low or high speed . Using a scan tool to see if the PCM will turn on the fans an checking engine coolant temp.data is the right way to diagnose this . Relay Driven Dual Cooling Fan Diagnostics

the air con fan comes on with the air con switch. the engine cooling fan comes on when the engine temp. censer reaches operation temp. most times the air through the radiator when driving is enough to keep the censer cool and the fan not working if you stop at lights for any length of time it will come on.

There is nothing to worry about. The cooling fans do not operate by engine speed, but rather engine temp. If the fans stopped working, then there would be a problem with either the cooling fan relays or the temp sensor which operates the fans. Otherwise, you are fine.

I have the same car. The cooling fan activates at 227F. Only one fan will engage at this temp, the other one[closer to the A/C compressor] won't engage unless the A/C is working. Try charging the system with half a can of refrig. It'll be tough retrofitting to R-134A, the LOW PRESSURE connector is under the air box pointing sideways about an inch from a large bracket. Try and find a 90 degree adapter of some type and go from there.

The cooling fan does not come on until the engine temp reaches 229 degrees. it is controlled by a cooling fan relay. Cheeck for power at the fan motor and check the relay. The A/C. If yuor a/c system is low on freon the low pressure switch on the accumulator will not complete the circuit for the clutch. Check the charge, voltage present at the clutch or the low pressure switch. You can install a jumper in place of the switch to test.

the fan turn on point on this model comes on at a very high temp gauge reading..not far from red or about 3/4 ways up...the engine will run quite a while before reaching this level. It should never go into the red which indicates problems but the design of the system gets it uncomfortably close. I've seen these needing to idle for 10 mins or so before the engine temp reaches the fan turn on point.One good thing about this design is when the fan does come on ,one should see immediate and noticeable drop below half in just a minute or two which indicates a good operating cooling system.

there is a relay panel under the hood with your engine cooling fan relay inside, a 12 dollar part, sounds to me like this relay may need to be replaced. There will be a diagram in your owners manual telling you exactly where it is located in your car. It should be noted that this relay has to be activated before the current reaches any fuse inside the cars fuse panel so your fan fuses can all be good but if the relay is not working the engine cooling fans will not come on. Be careful of dealerships I had one tell me it was a 3000 dollar wiring problem when it was only the relay.

When the car reaches a preset temp the cooling fan is supposed to energize a realy the turns the cooling fan on....But if you turn the air on you basicly bypass the temp switch because you must have air moving at all times for the ac.. So now i would be looking for a defective temp switch or defective relay.....

the cooling fans are run by a relay it's located in the junction box. check this. there is also a thermoatic sensor located near the fans next to radiator. the fans should free spin when the engine is off this is a good indiacator that it's not the fan themselves. if the relay checks out(run engine and switch the fan relay with the a/c clutch relay when the engine reaches 180 degrees you will feel the upper radiator hose get hot the fans will turn on a short time later iof they don't it's the temp sensor near the radiator if they do it's a bad relay...please rate this thanks