Went through the diagnosis steps in the FAQ - ruled out the temp sensor & found my way to the relay. The PO put a jumper wire in the large fuse box on the DS that shorts the fan relay to ground causing it to run constant. Disconected the ground wire & the fan turned off!
Now I just need to figure out what they spliced because the fan doesn't work at all with the ground short disconnected. Taking apart the bottom of the fuse box today to find out.
(Previous Z's - 92 TT stage I - 94 TT stage III) Current Z - 90 TT stage IV - being rebuilt