PCM or Not To PCM
 

I have a 95 Saturn and have noticed that if I sit idle in traffice, the thing gets hot...I mean into the red...!! If Im moving, it goes back down..this would be fine and dandy if I didnt live in a rush-hour ridden desert metropolis(Phoenix).. Ive read many articles..flush system, thermostat, fan sensor, engine bad...etc...Ive yet to find a resolution... We changed the therm(cheap place to start)replaced the fluids, still doing the same thing....the oil is fine, no water in it and the coolant was the correct color. My deduction is, its a fan issue-hence its fine when air is hitting it and heating up when its not. Now, Ive read this make and model has cooling issues, fan not kicking in until its in the red....etc.....
I will also mention, that the AC on this vehicle is no longer working, it blows air but it is not cold and the fan does not kick on when the ac is turned on.

The car isnt chugging or running rough at all, it actually runs fairly well, as long as it is MOVING!


The radiator was replaced not too long ago..I took it to a shop today and had a diagnostic test run it....they say the fan motor is bad and it needs a new pcm...Im searching around online and have read a few places that the PCM rarely, if ever goes bad. Could it be the PCM or is there something else I should check first???

Please help!!!

You do seem to have a problem there - let us see what we can do to help.

Since you took it to a shop today, I have to ask ... is it a Saturn dealer or some other establishment (Scotty's Scorpion Emporium and Automotive Repair), and how well do you trust them?

Assuming they are right about the fan motor, I would replace it first before worrying about any of the other issues. It is true, that the PCM does send a control signal to the cooling fan relay, but like you, I'm not totally convinced (right now) that the PCM is bad. Need to accomplish some testing to verify the control relay is or is not receiving the proper signals first.