Originally Posted by
racer55
The module you refer to is called the balance module.
It monitors the fuel level in both tanks and averages those levels to signal the gauge.
It also decides when the rear LP runs,when the front tank is approx. 2 gallons lower than the rear,the module pumps fuel from the rear tank to the front.
When the front tank has approx. 2 gallons more fuel than the rear tank the module shuts off the rear LP and the cycle repeats untill the rear tank is empty.
If your front tank was empty then you may have a problem with the front sending unit or the back sending unit or the balance module itself.
Troubleshooting time.