Aftermarket trailer mirrors from oem dl8 - Duramax
 

There are a lot of useful threads and you tube on this and some are more involved adding options. Once you get your head straight, it is relatively simple to reuse the ambient air temp sensor from the dl8 and put it on and wire ( 2 will not be used and at least one will need to be moved on the connector block) to the aftermarket trailer, manual fold, manual extend, power ,and defrost mirror ---passenger side. Cost me $60 at the dealer to find out it was a code 73 --cel engine malfunction. But for a total of $155 in all for both sides inluding $60 lesson, I am pleased.