My 190e 2.6 on statup blower worked for appr 2min cut off and if i drove car 10min blower fan started working again. This occurred repeatedly. I was advised to disconnect aux waterpump guess what blower motor ran flawlessly.
Earlier this week picked up a aux waterpump from salvage yard this one on startup will blow for 30sec and shutoff after 5min blows again. Again disconnected aux waterpump and blower works flawlessly. Try disconnecting aux waterpump.
My next step to replace electrical connectors which are corroded if that don't work then buy a new aux waterpump.