I pulled the connector off the ECT to check the voltage. Reads in range of normal voltage there & at relays. When disconnected the fan spins up and overheating light comes on in dash. So an NTC sensor makes sense.

If I took it off to test resistance, might as well just replace it, I guess. Unless our PT GT's don't work like non turbo models. I've bled the system & it just seems so quirky. One time it operates properly & the next it's overheating well past the middle marker on gauge w/o fan coming on.

Do you know anybody that's put on a aftermarket variable speed fan control, that can override the PCM control of radiator fan? I might try one of those just to keep safe. I've pulled the High Speed relay when it's gotten to 3/4 hot without fan coming on. Since pulling one of the relays (High Speed or low speed fan speed relay) works almost instantly to cool it back down.

Anyway.... thanks for your help. I'm off to buy a ECT sensor I guess!

Hello VNT, I have one of the same "05 PT GT Silver 5 Spd Conv" as you. I have an overheating problem and can't find an answer for it on the forum. Both fan speeds fail to turn on when running at operating temperature. I replaced the thermostat and waterpump metal feed tube and seal after I found it leaking the first time it overheated. No leaks now and it runs great, except for fan at either speed fails to come on. I turn the key and AC to on and expect to hear/see fan run, as I've read described on here. Nothing.... no fan. I pull the High Speed Relay in PDC and fan runs in low speed. When I replace it.... it shuts off. I pull the low speed relay and fan turns on in high speed mode. So I know the fan motor appears to be ok. I just wanted to ask you directly on this same vehicle, if you've ever had this problem and what it could be? Thanks!

Thanks for your help vnt, PTcraze

helllo vnt . this is doug from lewiston have a question for you . i have a 2004 dream cruiser high output turbo . i had oil changed to syn oil on sat .only had car a few months .dont know what it had for regular maint .i asume none . so know i want to do a tune up plugs and wires what plugs and wires should i put on .after tune up .i want to do trans fluid and filter car runs good has 77.000 miles . does need some body work .paint behind front mud flaps is chipping off and bumpers have a few scratches . got one est so far to repaint will get it painted this summer .thanks for you help.