AC Problem 2003 Saturn Vue

[jlstolze]

AC Compressor engages but radiator fan does not come on Compressor cycles
off on high pressure. When engine tempature activates fan everything comes
back to normal AC blows cold till fan goes off. Need to know were condensor
fan (radiator Fan) gets it signal fromm?

[fdryer]

Which engine? One or two cooling fans? The cooling fan circuits are in the fan control module by the battery. The fcm is controlled by the ecm that monitors coolant temperature, a/c demand, and a/c pressures. Yours seems to be cooling fan related - possibly a worn/burned out fan or fcm issues.

[jlstolze]

Sorry not to good at this forum stuff.
2003 Saturn Vue with 3.0 liter v6 24 valve with 1 cooling fan

[fdryer]

You're not the first nor will be the last to feel a little lost here. What's important is to retrieve the wealth of free information when you need it.

From the service manual;

Cooling System Description and Operation

Cooling Fan Control

The engine cooling fan system consists of one cooling fan and two relays. The relays are powered by the battery positive voltage circuit and controlled by a switched ground from the engine control module (ECM).

During operation, the ECM supplies the ground path for the cooling fan relays through the cooling fan relay control circuit. This energizes the cooling fan relay coil, closes the relay contacts, and supplies battery positive voltage from the cooling fan fuse through the cooling fan motor supply voltage circuit to the cooling fan. The cooling fan motor is grounded through its own ground circuit.

The ECM commands the fan on under the following conditions:

• Intake air temperature is above 4°C (40°F).
• Engine coolant temperature exceeds approximately 114°C (237°F).
• Throttle position goes below 89% for 15 seconds.
• A/C refrigerant pressure exceeds 2945 kPa (427 psi).
• A/C is requested and engine speed is below 4750 rpm.
• AF23-5 Transmission fluid temperature exceeds 130°C (266°F).
• VT25-E Transmission fluid temperature exceeds 140°C (284°F).
• When the engine coolant temperature exceeds 105°C (221°F) at key off, the fan will run for up to 300 seconds.

The ECM commands the fan off under the following conditions:

• A/C is requested and engine speed exceeds 6250 rpm.
• Engine coolant temperature drops below approximately 117°C (242°F).
• Throttle position is greater than 95%.
• Intake air temperature goes below 2°C (36°F).

Do you recall hearing the cooling fan running at two speeds? The wiring diagram shows a two-speed configuration and low speed may be faulty - there's a large ceramic resistor in one of the wheel wells that reduces voltage and current for low speed fan use. If this resistor is cracked then you lose low speed cooling. Low and high speed fan relays are in the underhood fuse block. You may try searching past threads about this resistor failing.

[stlmusic]

My first thought (mentioned in previous post) was the low speed fan resistor since it should almost always be running when the a/c activated. (Resistor is not used on high speed which would explain why when the fan kicks to high you get a/c but when the fan should drop to low, it actually shuts off and therefor no a/c) Once you know where to look inside the drivers side front wheel well, it's easy to see if it is broken to pieces. Only takes a minute or two to replace. You could also jump the low fan relay to see if the fan turns on. If it does, the resistor is good. My guess is that jumping won't turn on the fan.