GMC Truck Forum banner

1 - 20 of 21 Posts

·
Registered
Joined
·
1,765 Posts
Discussion Starter · #1 ·
i know there are alot of variables that effect that. but i put ls1 fans in my truck this weekend and i havent seen them come on. i drove it for 20min and i was gettin on it to see if the temp would raise but it never went over normal, i even let it idle for about 10min and nothing but its not running hot either. it was about 75* out when doing this also. if i turn the ac on both fans come on high but thats the only time ive seen them come on
 

·
is Bi-Winning and a
Joined
·
8,241 Posts
They may have run while you were driving or something and you never saw them come on. I doubt they would run very often at 75* too.
 

·
Registered
Joined
·
1,765 Posts
Discussion Starter · #4 ·
They come on when needed....
thanks for that :crazy:

They may have run while you were driving or something and you never saw them come on. I doubt they would run very often at 75* too.
thats what i thought too, i stopped every 5min or so, so they couldnt run for too long. but idk like you said at 75* they wouldnt run often
 

·
GMFS Member
Joined
·
845 Posts
I'm stabbing in the dark here, but how is it wired and where's it receiving the signal to turn on?
You say it came on when you turned on the A/C. Could it be that due to the way it's wired that's the only time they will come on?:think:
 

·
Registered
Joined
·
1,765 Posts
Discussion Starter · #7 ·
they are turned on by the pcm and i am using the blackbear harness. since the fans do come on that means they work and have a power source/ground. pin 42 (or whatever i dont remember which) must be hooked correctly my only concern is that pin 33 may not be fully connected
 

·
Registered
Joined
·
8,303 Posts
Justin (JustinSS) told me during my tune, but I can't remember. I think they come on around 220* from the factory, but Justin set mine to come on around 190* or 200*.
 

·
Registered
Joined
·
1,765 Posts
Discussion Starter · #9 ·
me and justin talked about that too but my tune was awhile ago so i dont remember what he set it at
 

·
GMFS Member
Joined
·
845 Posts
Could the thermostat be stuck open?
 

·
Registered
Joined
·
8,303 Posts
me and justin talked about that too but my tune was awhile ago so i dont remember what he set it at
Honestly, even with Justin's new settings... I don't really notice mine coming on that often. It hasn't really gotten that hot here yet though.


I haven't been paying super close attention, but it's been around 80* here and I don't think mine have come on while driving to and from school. (Short 5 mile trip.) I'm not really idling in traffic either though.

It was 95* a few weeks ago and I remember hearing them while driving around in a parking lot and at idle.
 

·
Registered
Joined
·
19,437 Posts
They also go off when you get over 35mph. One of mine runs when my ac is on but you can here them when they kick on when its just idleing but the stay one for like 2min and then go off
 

·
Registered
Joined
·
4,874 Posts
i have mine hooked up and it seems like they turn on no matter what. i only have one pin hooked up tho, blue 42 IIRS. i saw there was a green pin to also hook up? but didnt see anything on the PCM that was green... i mean they work and have been working so i havent been too worried about it.
 

·
Registered
Joined
·
8,303 Posts
Whoops, I was wrong. I was out driving tonight (at 72*) and I heard them humming while I was driving through a residential area (about 30mph). They were pretty quiet though, there must be more than one speed. They get pretty loud when it's 105* and I'm idling in traffic.
 

·
resident pyromaniac
Joined
·
7,499 Posts
mine hardly ever come on when ambient is in the 60s-70s...i wouldn't worry about it. sounds like they're normal to me.
 

·
Registered
Joined
·
3,481 Posts
just let it idle for 20 minutes or so after a freeway run. If they don't come on it will overheat fast. Keep checking the temp and of course shut her down if they don't come on, but hopefully they should.

On my stock 06 Sierra they seem to be on quite often, but that is b/c I have auto climate control and the AC is always on. Once I was checking the trans fluid and had it idling w/ climate control off, and the truck ran hotter, until one of my fans kicked on - can't remember which one though....... hope this helped.

Mr. 960
 

·
GMFS slowest truck :read:
Joined
·
5,501 Posts
just let it idle for 20 minutes or so after a freeway run. If they don't come on it will overheat fast. Keep checking the temp and of course shut her down if they don't come on, but hopefully they should.

On my stock 06 Sierra they seem to be on quite often, but that is b/c I have auto climate control and the AC is always on. Once I was checking the trans fluid and had it idling w/ climate control off, and the truck ran hotter, until one of my fans kicked on - can't remember which one though....... hope this helped.

Mr. 960
both fans should come on if wired up like stock. its a fairly complex wiring system they have, but they basically share the voltage at low speed and get full voltage at high speed.
 

·
Registered
Joined
·
1,765 Posts
Discussion Starter · #19 ·
yea my understanding was that they both ran on low as needed and both run on high with the a/c on. the truck has be running at the exact same temp as before i put them in, but ill do some more checking this weekend
 

·
......
Joined
·
1,847 Posts
Mine usually don't come on unless it's over 85 outside. It really depends though...they usually only come on in city driving
 
1 - 20 of 21 Posts
Top