200 TQ had bad thermostat, now no cooling fan...

[Frank Martin <FMartin@ithaca.edu>]

Hi folks. Anyone BTDT or have ideas on the following?

My 1990 200TQ began overheating a week ago, on a commute home. When
home, I let it idle for a few minutes, with an eye on the temp. gauge.
Soon, the alert chime went off, then the reservoir blew off pressure.
During this time, the cooling fan never started up. So, my first thought
is a problem with that. In the meantime, I saw a couple posts here re:
similar symptoms of overheating, pointing to a failed thermostat. 
Last Saturday I put a new thermostat; I'm sure that fixed the original
problem, since the car had been overheating at speed, on the level.

However, I then noticed that the cooling fan was still not coming on. I
found that there was an 80A fuse link in the wiring - when I touched it,
it fell apart. So, I think, AHA! But it doesn't seem that simple. When I
tried bridging that gap, the fan came on a full force all right, but
stayed on whenever the ignition key was turned on. 

So, I'm stymied, again. Tonight, I'm putting a new thermo relay in,
along with a new 80A fuse strip. I sure hope that does it. Any other
ideas??

(I did try switching two similar relays in the fuse box, no difference.)

TIA,

Frank M.
1990 200TQ
Odessa, NY, USA