je suis pas expert, voici le code complet avec les déclarations existantes, en supprimant *1 j'ai pas d'erreur certes mais j'ai toujours mes virgules.
Sub Vers_Wgs84()
Dim lg As Integer, i As Integer, x As Double, y As Double, Resultat As Wgs84
With Sheets("Chantier")
'lg = .Cells(Rows.Count, "L").End(xlUp).Row
For i = 37 To 47
y = .Range("L" & i).value
x = .Range("M" & i).value
Resultat = Lambert93ToWgs84(x, y)
.Range("D" & i).value = Resultat.lat
.Range("D" & i) = Replace(Range("D" & i), ",", ".")
.Range("E" & i).value = Resultat.lng
.Range("E" & i) = Replace(Range("E" & i), ",", ".")
Next i
End With
End Sub