thanks for trying to help me, actually there is a thermal sensor in this cable, I was thinking if some one out of there knows, may be some one who is would be repairing the MacBooks.What makes you think there is such a thing as a palm rest sensor? I doubt anyone outside of Apple and MAYBE authorized retailers have access to the schematics of Apple hardware to be able to tell you what chip is what. iFixIt identifies the more common components by the fact that they are designed/made by 3rd parties and are unique in their use (i.e., WiFi/Bluetooth chip, CPU, etc.)
My guess is that there is no special sensor that detects the palm other than the trackpad itself with some clever software that can determine the points of touch or area of touch to know that it's more than just your fingertips.
This is the route I would suggest as well. A simple/fast swap of failed part for working part....replace the whole trackpad and cable
I agree. After checking eBay again...some sellers are selling just the cable. But some sellers are charging almost as much for just the cable...as other sellers are charging for both the cable & trackpad combo. I'm rather get both for a few dollars more...but OP could save a some $$ buying just the cable.If reseating the cable doesn't work, it needs to be replaced. The trackpad itself has ABSOLUTELY NOTHING to do with the issue. Don't waste money. Just buy a new cable if seating it doesn't cause the fans to slow their roll.