Extra plug near ac canister...

[xbauer39]

New to the gmc yukon...its a 2004 yukon xl. Today i noticed a extra plug coming out of firewall near the ac canister...dosent seem to go to anything. Anyone happen to know if its nust some type of service plug or am i missing something? Thanks in advance

 

[PG01]

Welcome, pics would help though for future ref. If it has a blue plastic connector thnnits something for a dual batt setup.

 

[xbauer39]

Thanks! Yes, it has the blue clip.