Does C5 corvette have fan speed control module and where is it located . If it does not then what would control them besides the relays. Thank you

 

The PCM controls the fan on and off

 

As stated the PCM controls the fans through the various relays. They run in series (6 volts each fan) for low speed and parallel (12 volts each fan) for high speed.

 

SaccityCorvette has a controller that turns fans manually.

https://www.saccitycorvette.com/HardWireCoolit.html

 

Thank you for the information and your time

 

Are you having fan issues? Over heating issues?
What is the problem? Might save yourself some trouble and money if we knew what the issue is... just sayin

 

Here is a description of how the fans work and at what temps they are turned on and at what temps they go to high speed operation.
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 and ignition 1 voltage from the underhood electrical center. The ground path is provided at G102.

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 2 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 2 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.

The low speed cooling fan is commanded on when the coolant temperature reaches 108°C (226°F). It is turned off if the coolant temperature lowers to 104°C (219°F). The high speed cooling fan is commanded on when the coolant temperature reaches 113°C (235°F). It is turned off if the coolant temperature lowers to 108°C (226°F). When the A/C is on and the coolant temperature reaches 85°C (185°F), the low speed cooling fan will be turned on at vehicle speeds less than 56 kPh (35 mph).

People are always running around worrying about their temps because they see the numbers on the gauge. These cars are designed to work with high coolant temps and have no problems operating at the temps you indicate. As you can see the fans don't even get turned onto low speed until the temp hits 226 and don't go to high speed until the temp hits 235 degrees. At an autocross where we were running in heats and cycling through the runs quite fast I saw a 242 degree coolant temp on my C5Z for most of an event.

Bill