Hi Ernie

Good, that makes sense one fuse being on all the time, the other is on
with the ignition switch on. The following tests will assume you have
the ignition on so you'll need 12V on both those contacts on the relay.

Ok, you should have 12V on one side of  the thermo switch with the
relay plugged in. I should have made that a little clearer. Basically,
on one side of the coil you have 12V and, because the switch is open,
you should see that 12V on one side of the thermo switch as well.  It
is weird that you have continuity on from the thermo switch to the coil
- I wonder if your socket has a bad connection. They are pinch type
connections, so maybe they are somehow bent out too much where the
relay just doesn't make contact. Since your multimeter probably has
nice fat contacts, you see continuity. Inspect the socket, definitely
-- you can bend those contacts back carefully, if that is what's
needed.

If that looks ok, put a thin wire in relay socket pins and carefully
plug the relay back in. That wire will just be pinched in by the relay.
The contact we're intested in is the coil side of the relay that
doesn't directly go to 12V --  this way you can see what the relay
sees. We're going to test the circuit live this time.
Get a temporary wire (clip lead or something like that) and hook it
between ground and this wire -- if you see the fan turn on, your relay
(including socket) is good. If not, check all contacts on the socket.

if it passes that test, unhook your temp ground connection and measure
the voltage across that point and ground. You should see 12V with the
thermo switch open. Shorting the thermo switch should make it go to
near 0 volt. If you don't seen a change, the wire from the switch to
the relay must be bad or the ground is bad.  That cliplead test we just
did basically emulates what the thermo switch does and we know the
relay works -- it has to be wiring to the thermo switch.
If you see it change but not to zero volts, it means you have some
resistance in the path somewhere. I'd check the ground connection to
there thermo switch. Get your clip lead and clip it to the non-ground
connection of the thermo switch and ground. If the fan now turns on,
your ground connection to the switch is bad. If it doesn't turn on, the
wire from the switch to the relay must have some resistance -- perhaps
try clipping a lead directly from the switch to the relay and see what
happens. It is hard to believe that the wire changed its resistance,
but there is a junction connection according to the schematic. One side
of that junction does go to the ECM so let's hope we don't have to look
in that direction.

Btw, what happens when you turn on the AC? Do both fans turn on?

These problems are a pain to find but think how great you'll feel when
you keep that money in your pocket :)
You'll get it.

If you need quicker response, you can email me if you'd like.
Remco

Thanks for the clarification.
Unfortunately, Ernie is seeing power on both legs so where the fuses are is
moot:  It would have been nice for him to find just a fuse blown.