Cooling Fan doesnt kick on - SOMETIMES

["iqmpike" <iqmpike@xxxx>]

Just replaced the radiator on my Delorean (actually the entire 
cooling system in the front, radiator, and hoses)...

Anyhow... while it was sitting in my drive way, it hit the 220 mark, 
and the fan didn't come on... it then kept heating up.... so I turned 
the engine off...

I turned the air on, which I understand is supposed to FORCE the 
front fans on, and it didn't....

Next day, I went out.... the fans kicked on at 218 or so, and when 
the air was on, the fans came on....

Then again today... same thing, they didn't function on either...

Is this a common problem, and if so, what do I do to fix it?

I would have thought it was a temp sensor.... but beings it doesn't 
kick on with the AC I assume it's a relay or something?

Any help appreciated.... thanks.

Mike