Was the system topped off properly after the trans install? If the trans oil cooler was removed with the tranny you will have lost some coolant. The fan not working can be electrical or a coolant flow problem. If the light was on due to low coolant that can prevent the fan from operating properly. Again, low coolant, if the pump starts sucking air the coolant will not flow properly to the radiator so the fan switch in the radiator will not turn the fan on. Same condition also renders the temp gauge less than accurate. No coolant flow, the gauge will not rise until after you make steam. 

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of John Rodgers
Sent: Wednesday, May 25, 2016 8:26 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Radiator fan

Finally, the Carat is home! New engine, newly overhauled autotranny. And the latter is so sweet! Can't even feel it shifting gears between 2nd and 3rd gear, and it's barely detectible between 1st and 2nd.

Picked Carat up at Floss Transmissions today, and drove home. Would you believe I got within a stones through of my house and the low coolant light came on. By the time I got parked, the temp needle was already clear of the red light on the hot side. I shut down immediately. No fooling around. I'd hate to fry a brand new engine. With the engine off, and all being quiet, I realized there was no radiator fan  running. I thought "Now what?" I decided to leave it til in the morning when its cool to work on it.
Besides, I need some input from anyone who has dealt with this fan. I don't even know where to start. BTW, there was no coolant leaks anywhere.

Suggestions anyone? Would really be appreciated!

John