New to list (Migrant from the type2.com list)

I am the new proud owner of a 1985 gas powered, water cooled, 1.9 liter Weekender Vanagon.

The van runs hot and the temperature gauge runs close to maximum in stop and go traffic and cools down at highway temperatures (just the opposite of my 1970 bay).  I figure the electric fan isn't kicking in.  I don't have the Bentley manual yet but figure I can, through trial and error, disassemble the front grill and get access to the fan.  Now if I can convince myself that the fan actually works, then I figure it has got to be the thermostat switch.  Does this line of reasoning seem reasonable?, are thermostat switches known for failing?, is this a huge undertaken?, Do you have any words of wisdom or advice?  I've only had this bus for about two weeks and so am definitely green and appreciative of any advice.

Thanks for your time,

Juan