Quote:
Cooling Fan Control
The engine cooling fan system consists of two electrical cooling fans and three fan relays. The relays are arranged in a series/parallel configuration that allows the Powertrain Control Module (PCM) to operate both fans together at low or high speeds. The cooling fans and fan relays receive battery positive voltage, from the underhood fuse block. The ground path is provided at G106.
During low speed operation, the PCM supplies the ground path for the low speed fan relay through the low speed cooling fan relay control circuit. This energizes the cooling fan 1 relay coil, closes the relay contacts, and supplies battery positive voltage through the cooling fan motor supply voltage circuit to the left cooling fan. The ground path for the left cooling fan is through the cooling fan 3 relay and the right cooling fan. The result is a series circuit with both fans running at low speed.
During high speed operation the PCM supplies the ground path for the cooling fan 1 relay through the low speed cooling fan relay control circuit. After a 3-second delay, the PCM supplies a ground path for the cooling fan 3 relay and the cooling fan 3 relay through the high speed cooling fan relay control circuit. This energizes the cooling fan 3 relay coil, closes the relay contacts, and provides a ground path for the left cooling fan. At the same time the cooling fan 3 relay coil is energized closing the relay contacts and provides battery positive voltage on the cooling fan motor supply voltage circuit to the right cooling fan. During high speed fan operation, both engine cooling fans have there own ground path. The result is a parallel circuit with both fans running at high speed.
LS1
The PCM commands low speed fans on under the following conditions:
Engine coolant temperature exceeds approximately 108°C (226°F).
When A/C is requested and the ambient temperature is greater than 10°C (50°F).
A/C refrigerant pressure exceeds 1482 kpa (215 psi).
After the vehicle is shut off if the engine coolant temperature at key-off is greater than 140°C (284°F) and system voltage is more than 12 volts. The fans will stay on for approximately 3 minutes.
The PCM commands High Speed Fans on under the following conditions:
Engine coolant temperature reaches 112°C (234°F).
A/C refrigerant pressure exceeds 1710 kpa (248 psi).
When certain DTCs set.
|
I would confirm the tune didn't foul up fan operations first. Then, observe the data stream and see if and when the fans are being commanded on. If its good on the pcm side, we'll get into checking the wiring. You could always jump the relays to test the fans or jumper straight to them if you are unsure of wiring that may have been altered. If its overheating at idle, the water pump shouldn't have trouble keeping up. Coolant is full and bled and coolant temp sensor for computer is working correctly?