Motorists have been reporting issues with the lights flicking on and off for months.
It seems to happen at peak times and caused drivers to make their own way through the busy junction unaided.
A Spokesperson for Highways England said:
“We have checked all our equipment at the junction and have found no issues."
“Our investigations suggest this is an issue with the reliability of the power supply and we have raised this as a matter of urgency with Electricity North West."
A diesel generator has been placed at the scene in hope it temporarily stops the problem.
Electricity North West say:
“An issue with low volts at the local substation has been causing the traffic lights on the junction of Fleetwood Road and Garstang Road West to flicker."
“Our engineers have fitted specialist equipment to monitor the voltage and they have been onsite on Tuesday and yesterday to try and rectify the issue."
“They are continuing to monitor the situation and they will be attending site as soon as possible to help carry out a permanent repair.”