Hi

try

Code:
Option Explicit

Sub kTest()
    
    Dim tColor      As Long
    
    tColor = Evaluate("=LOOKUP('Sheet3'!S45,{-9.99,3;-0.03,46;0,5;0.03,4})")
    
    Sheets("Sheet3").Tab.ColorIndex = tColor
    Sheets("Sheet1").Tab.ColorIndex = tColor
    Sheets("Sheet2").Tab.ColorIndex = tColor
    
End Sub