Yes another overheating question.

[Knotsobright1]

I have a 2001 Pt with 66,000 miles. For about the last couple of weeks I have had some serious overheating problems. Sometimes when I start the car (with the AC on) the fans come on and sometimes they do not. I have changed thermostat,flushed and filled fluids. The car will overheat at idle or when driving down the road 35-65 mph. I have removed fans and when I test with jumper wires they work fine. Is there a way to test the low and high speeds? The radiator feels warm to the touch so I don't believe it to be water pump and no exhaust smell or etc in new anti-freeze. Any help would be appreciated.

[Knotsobright1]

Also installed new cap. I know this has been asked a lot here on this forum but there never seems to be a cut or dry answer.

[CREWZIN]

Your answer was in your first statement. The fan "sometimes" comes on. The fan should always come on if the A/C is on or even if you have the control set on "demist/defog" because that turns the compressor on.

If it's not coming on, that narrows your problem down to the fan motor (probably 99% of the overheating problems), the relays or the PCM itself.

Now after saying that, you also have to not have a bad head gasket or trapped air in the cooling system for it not to overheat.

[Knotsobright1]

Now with the fan out the car anytime 12v is applied they turn on. I have checked relays and being a owner of to many neon's and other mopar products I know its not the head gasket. I have searched and searched this problem a lot. Is there A flash for the 2001 PCM or just 03 and later? No other electrical or operating problems have been going on so PCM doesn't seem to be issue. I know you guys from reading around have been hearing about this for years I just don't want to be the next poster saying " I just spent $3000+ and it still overheats."

[CREWZIN]

There's a flash for the early 2001 PT but I don't think it has anything to do with the fan. Te early 2000's didn't have the kick down feature on the cruise control meaning it wouldn't drop down about 1 mph when you hit the cruise control. The flash was for the fix of that.

I'm stumped as to why your fan won't come on when it's all hooked up if the relays are good and you think the PCM is OK.

The wiring diagram shows everything you checked except the No #5 fuse in the PDC (Power Distribution Center) under the hood. That's for the fan itself. The PCM has a high & low speed fan relay control built inside that controls the actual relay in the PDC. I think the only way you can check that is with the scanner from the dealer or mechanic.

[Knotsobright1]

I even went as far to jump the fans so they run when the ignition is on and they ran but car still overheated. Not quickly. Would go about half as normal but once it started it went up fast getting 3/4 I would shut her down.

Just went out and swapped the horn relay and High speed fan relay to verify working and horn works so relays work.

[CREWZIN]

Well, othre things to check are a clogged radiator or condenser, air in the cooling system (not bled properly) or head gasket problems.