Coolant temp difference.

Hello. I am getting a different temp reading on my VDO temp gauge compared to the reading on my scanmaster. Is there a way to connect the coolant temp sensor on TOP of the manifold to my VDO gauge? Any ideas on how to get the readings to match up would be appreciated. And, yes I have replaced the VDO gauge and the sender. Still does not match up with reading from the scanmaster. Thanks.