Aaron Davis

Ok I got an 06 Uplander(hence why I'm on the Uplander thread,lol) anyway it's not overheating,I'm getting proper flow through the system,but I've NEVER heard the fan run in the 5 months I've had it. Today was the first 70+ degree day that the temp guage went a little past half going red light to red light through town, getting nervous I blasted the heat,the temp dropped a bit immediately then once I started driving outside of town,it went right back almost instantly to normal operating range. So is it possible for the engine to NOT overheat if the fan isn't working or am I just being Paranoid? I just don't want it to be overheat once summer hits,I really love my Uplander

tech2

start the engine and turn on the a/c, if the fan doesn't come on you have a problem....if it does you know the fan works for the ac but not necessarily for an over heat condition. the fan controls for a high temp are based on ect temperature. if you unplug the ect connector the system may turn the fan on as a precaution.

not sure what temp the pcm needs to see to command the fan on.

12three

these vans are odd, in my opinion, bc they dont command the fans onto low until it hits 225 degrees, which is actually the first hash after dead-center on the gauge... obviously AC-on will turn the fans on but if your ac gets a hole then you are going to run at 225+ regularly unless you put in a new switch or fix the AC...

225 is, IMO too hot. the tranny is the biggest issue with 225..., bc the magnet in the pan gets too hot and loses strength and starts shedding ferrous stuff... plus the solenoid picks up ferrous stuff and starts shifting weird... there is a tsb for the oemmagnet... should probably be a recall not a tsb in my opinion... the new ones are much larger and stronger...

the other issue is that one fan can die and not throw a light... if one fan dies and your AC dies then your remaining fan wont click on until it gets the signal to run on high, which i believe is at 235 degrees... bc its wired in series for low (225) and parallel for high (235 i believe)... so if one fan is out you will lose 'low' completely and have no fans running at 225...

the moral of the story is: fix ac/fans asap... or rewire asap...
you can cut a dead fan out of the low circuit to get the working fan to run on high at 225 by snipping the +&- going to the dead fan and tying them together... i believe this may end up popping a fuse if it ever gets hot enough to command it onto the 'high' circuit (235 degrees i believe, definitely the second hash after dead center)

Aaron Davis

Yes it is weird,I've had the van for I think 4/5 months now,it hasn't overheated,but I now see it's been running hot,instead of finding whatever relay or fuse was blown,I just wired it directly from the fan to a hot spot in the fuse box,both fans come on as soon as I turn the key now,my dad did this to ALL his GMs when I was growing up. It runs a heck of a lot cooler now,only on the second Mark on the guage whatever temp that is. I really don't like that it don't tell exact temps like my wife's Cobalt does,but whatever it's fixed,next on my list is brakes and rotors,ah the joys of buying used vehicles!

12three

honestly i think you would be better off letting it go to 225 than running it that cool... i dunno what temp that is, but i assure you it is too cold. your mpg will be in the gutter...
the way to get the numbers on the gauge is thru obdii... look up elm327 on amazon or whatever... its about $15 and torque app is about $5... the two of them will get you access to a bunch of sensors

12three

the only temp gauge numbers i roughly remember are as follows:
the center of the gauge is 190-220F, then the first hash to the right of dead center is 225, and the second hash to the right of dead center is 235 i believe. fans are commanded onto low at the first hash after dead center and high at the second hash right of dead center.
the gauge is not to any scale, its basically just 'if its in the middle its ok, if its to the left its too cold, and if its to the right its a bit warm or too hot'

you will run into probs if you run the fans on full blast. it will throw a code, your mpgs will suffer, higher friction, your fans will prolly break, and your electrical system will be taxed bc the fans draw a ton of amps

tech2

the fan runs full blast anytime the a/c is turned on...its designed for it...nothing will break, mpg loss will be negligible, full ac compressor and fan would be a 1mpg loss; most of that from the compressor.

12three

i think he said it wasnt coming up to temp tho...

tech2

..ok.

12three

i dunno i dont think it would come up to temp with the fans on full blast, i might be wrong... i took him for his word there... the temp drops 5 degrees immediately on low on mine and my fans were scavenged from the junk yard and missing part of the shroud...

you are correct if it still comes up to temp with fans on, i am correct if it never comes up to temp...