IF function in excel is too long. How to simplify?

I have written a long IF function, and I have more to write but excel is telling me that it is too long. How do I simplify it? I'm using Excel 2003. THANK YOU!

In Column K3, I have a drop down list of Types of Defects, then this IF function is in column L3 to appear a specific Defect Description based on the Types of Defects selected in column K3.

=IF(ISTEXT(K3)=TRUE,IF(OR(K3="Abnormal Finishing",K3="Bending Mark",K3="Bent",K3="Contamination",K3="Crack",K3="Damage",K3="Dented",K3="Discoloration",K3="Finger Print",K3="Flow Mark",K3="Gap",K3="Insufficient Paint",K3="Scratches",K3="Rusty",K3="Stain Mark",K3="Standoff Mark",K3="Tool Mark",K3="Warpage",K3="Water Mark",K3="White Mark",K3="White Spot"),"Cosmetic",IF(OR(K3="Angle Out",K3="Dimension Out",K3="Fitting Problem"),"Dimension",IF(OR(K3="Assembly Misalignment",K3="Fan Broken",K3="Fan Not Functioning",K3="Assembly Wrong Orientation",K3="Missing Component",K3="Missing Rivet (Assembly)",K3="Part Warping (Assembly)",K3="Rivet Loose (Drop) (Assembly)",K3="Rivet Wrong Location (Assembly)",K3="Rivet Wrong Orientation (Assembly)",K3="Screw Loose (Drop)",K3="Screw Stuck"),"Assembly","ERROR"))),"ERROR")