Can't figure out what this electrical connector is for...

[Marianne W]

We've been rebuilding our 06 SR5 and can finally see the light at the end of the tunnel. (We started a year and a half ago.) There is an electrical connector in front of the A/C condenser and I cannot for the life of me figure out what it is for. It is the grey one on the left. It isn't for the ambient air sensor and the other wire is for the horn.

Can someone please help.