I have a 2005 Suburban that I recently purchased to replace an 04 Yukon XL. I have noticed that when I turn on the electronic defrost, it is much slower to defrost RV Mirrors/Rear Glass than the Yukon XL was or my 05 Silverado. On both of those vehicles the defrost starts melting the frost almost immediately once button is pushed but on the 05 Suburban, it is much slower to work. It will defrost but takes about 4-5 minutes to have any effect. Both mirrors and rear glass are slow so I was thinking it might be a core component of the system. Is there a Defrost module or something similar that I can replace to see if it improves defroster performance? Would a defective defrost relay cause this type of issue? Thanks!

 

in most cases it either works or it doesn't, could be low amperage issue but without testing its hard to say

 

Thanks, that's kind of what I was afraid of. Was thinking if I was lucky, maybe there was a module of some kind that could be replaced.

 

check the connections on the grid at the rear window.some times they will get corroded and cause a voltage drop on the grid.