'99 SW2 fan not cycling...
 

I have replaced:
thermostat
fan relay
ECTS and pigtail (bought OEM)
Checked all fuses, all appear good...radiator fan won't cycle automatically, what am i missing?

try wiring fan connector directly to battery to ensure fan motor itself is not defective

It could just be a dirty, corroded connector. Do what derf said and make sure it's not a dead motor. Does it come on if you turn on your a/c?

Yep, fan comes on fine if the ac circuit is enabled...can't figure out why it won't cycle automatically...

Gotta be a loose or dirty connection between the relay and then fan, I'd think. BUT I'm not a mechanic and sure as hell am not an electrician either. I just do what I have to do and have kept my cars running for over 40 years. I don't work on other peoples cars because they keep expecting you to do more and more and get pissed when you start charging them!

Thanks for the input, Ruby...i'm totally mystified here, and wish i was a decent enough mech to figure this out...

If fan comes on w AC engagement, we know
1)relay is good and socket is clean enough
2)fan motor is functional
(Shoulda asked that first--sorry)

What we don't know is
1)if the resistance response of the ECTS is correct (I believe the voltage drop across the ects is what triggers the PCM to command the fan relay to engage)
2)if there is, per Rube, a wiring problem betw the ects and PCM.
________
How is the dash gauge behaving? My Sattys both don't kick in the fan until right below the start of the red. Always been that way. Does the gauge get that high?
Is the car actually overheating? Is the gauge indicating an overheat?
________

Note that the ects info lets the pcm infer the coolant temp and also drives the temp gauge on the dash (indirectly)

The gauge is acting perfectly now that the ECTS and harness are new...before it was a little notchy and occasionally would not register anything until 10 minutes into the drive...i will run it today and let it get above the normal engagement point and see if the engagement point might have been reset somehow...

.....aaaaaaand success...temp got about 1/8th of an inch higher on the gauge than it used to kick on and came on like nothing bad had ever happened...it used to kick the fan on right at the half mark, now it kicks it at just above the half mark, and drops it down to the other side of the half mark...i'm happy!:p

Well, all righty then. If you're happy then I'm happy. I can't speak for the rest of the guys.