Scotland TranServ will be replacing the traffic signals on the A76 at Crawick Bridge near Sanquhar.
The current lights are nearing the end of their life and require full replacement, along with poles, controllers and underground cables.
Principal lighting engineer Aled Davies said: “This is an important section of the A76. Traffic volumes currently remain low and the programme can therefore be carried out safely and with the minimal disruption.”
Daytime lane closures will be put in place from July 6-24.