Cooling fans coming on when not needed

[Nutro]

2014 Tahoe PPV with 100K on it. Some times I can hear the cooling fans turn on before the truck reaches temp or I can sometimes hear it just come on randomly. Coolant is full, A/C and/or Defrost etc is off.

I replaced the main relay for the fans, I also installed a new GM coolant temp sensor yesterday. Today it is 49 degrees out. I just went to Chik-Fil-A for my daughter (3 miles away) and on the way home, I noticed the voltage gauge was down. I got home and popped the hood and both fans are on. I'm lost

 

[Fless]

There are several threads on here, and they generally are recommending changing the thermostat. What's the full operating temp you read with a scanner?

 

[Nutro]

I posted in a couple of those just now. I'm embarrassed to admit, I don't have a good scanner YET but have a little Bluetooth OBDII dongle and an app called Torque. I just went and drove it and watched like a hawk. Dash showed 210 but I was seeing 190-ish on the app. I pulled into a gas station and popped the hood. Both fans were spinning on low. The volt gauge showed close to 14 at idle. I shut it off, got gas and went for a little drive with some slight throttle accelerations. The temp got up around 195-197 then dropped back down to 190-ish. I never heard the fans come on high speed. I did this a few times and it seemed the temp would climb to about 195-198 then come back down to the 190-194 range.

I got home and checked and still both fans on low speed and voltage showing 14v. Its so odd.

 

[Foggy]

I posted in a couple of those just now. I'm embarrassed to admit, I don't have a good scanner YET but have a little Bluetooth OBDII dongle and an app called Torque. I just went and drove it and watched like a hawk. Dash showed 210 but I was seeing 190-ish on the app. I pulled into a gas station and popped the hood. Both fans were spinning on low. The volt gauge showed close to 14 at idle. I shut it off, got gas and went for a little drive with some slight throttle accelerations. The temp got up around 195-197 then dropped back down to 190-ish. I never heard the fans come on high speed. I did this a few times and it seemed the temp would climb to about 195-198 then come back down to the 190-194 range.

I got home and checked and still both fans on low speed and voltage showing 14v. Its so odd.

That's pretty normal.. Once the fans hit the activation point on the low speed,
the factory settings keep them on for a very long time and down to about 195* ish.
The gauge may as well be a dummy or a H/C type ... Don't ever rely on it. There
is no fix or adjustment.. For real Coolant Temp, use a scanner of some sort.

 

[DodDel5-3-6L80e]

2014 Tahoe PPV with 100K on it. Some times I can hear the cooling fans turn on before the truck reaches temp or I can sometimes hear it just come on randomly. Coolant is full, A/C and/or Defrost etc is off.

I replaced the main relay for the fans, I also installed a new GM coolant temp sensor yesterday. Today it is 49 degrees out. I just went to Chik-Fil-A for my daughter (3 miles away) and on the way home, I noticed the voltage gauge was down. I got home and popped the hood and both fans are on. I'm lost

My Tahoe SSV fans would go on high for no reason whatsoever. Chevy sent me a recall for the fan system. Look yours up, it may be included in the recall. My boarder patrol teuck has an "enhanced cooling package" or "cooling package upgrade" with upgraded cooling fans among other things. Special heavy duty radiator cost me $700 for the part alone from Chevy(only place that had it)I fixed the fan issue myself with HPtuners. The fans have a low, medium, and high that have a few adjustments, such as RPM and coolant temp. My thought is it may not be an issue with the hardware but rather the software.

 

[j91z28d1]

the ex cop cars have 3 speed fans? that's interesting. the normal ones only have low and high.

they hybrids have 3 speeds too. a scanner can show you what's being requested by the ecm. and you can use it to manually activate all the speeds as a test.

 

[Nutro]

This Tahoe does have an open recall for the Airbag and the cooling fan thing. I just installed a new GM radiator and coolant levels are perfect so far. Maybe it has to do with the recall? The local dealer ordered my airbag so hopefully they'll get it in and fix the cooling fan issue. I just don't see how that recall would affect the fans coming on. I thought it was more about water/corrosion or something.

 

[Nutro]

Had the recall done and its still doing it. I was watching it this evening and on the dash it shows 210 but the ECM is showing it never getting above 194-195 with or without the fans on high. I might just throw a new thermostat in it. I see RA has a GM one that shows 195 and an AC Delco one that shows 190 opening temp. Either one should work, correct?

 

[j91z28d1]

Had the recall done and its still doing it. I was watching it this evening and on the dash it shows 210 but the ECM is showing it never getting above 194-195 with or without the fans on high. I might just throw a new thermostat in it. I see RA has a GM one that shows 195 and an AC Delco one that shows 190 opening temp. Either one should work, correct?

oem is better. it's actually made my MAHLE for them and is 187deg I believe. and there's always a plus or minus spec for that. there was a thread where I guy bought 5 stats and every one of them opened at a different temp testing them on the stove. aftermarket lower temp ones like the cheap motorad brand are pretty random.

refresh my memory. what is your issue? it sounds like it's working fine? LS engines are funny, they have the thermostat on the cold water side after the radiator before entering the engine but the Temp sensor is in the drivers side head. one of the hottest spots. they mostly run around 195 and cycle around a bit on a scanner. that's the actual exit water temp. the dash doesn't really even matter. but if you look the thermostat is actually a much lower temp. usually about 10deg lower rating. something like 184 or 187, I can't remember right now. and they have a bypass built in to help warm up so the fact that your fans are on and you can get it below the temp is normal. when it's in bypass you could be driving in below zero Temps and still be at 190deg engine Temps while the radiator is freezing up.


if you want to adjust the temperature your fans come on, hptuners will allow you to do this to a point.. there's some hard coded limits to it.. guys run into them trying to put a 160deg stat in the car and the fans won't tune on early enough to match. it's hard coded limit hpt can't over ride. but shouldn't be a issue if you're wanting them to turn on later.


also remember there's a fan table for ac pressures/temp too. so as your high side pressure goes up the fan speed will increase for that. ac high pressure takes priority over coolent temp.

this isn't our trucks, but you get the idea. same basic map in both.

 

[Foggy]

Do NOT rely on the temp gauge on the dash...
It will show 210* anywhere from 180* to 225*
Its basically a dummy light
You need some type of scanner to read the actual temperature.
As shown above, the factory doesn't turn off the low speed fan completly
until 199*-203*
On mine I zeroed out the fan activations below 199*...
That factory still shows around 10-15 at 192...
BUT the activation isn't until 40% or above ... it's just the deactivation that
takes too long on factory setting IMO and takes too long to go to high speed
activation which is about 80%.

 

[Doubeleive]

My Tahoe SSV fans would go on high for no reason whatsoever. Chevy sent me a recall for the fan system. Look yours up, it may be included in the recall. My boarder patrol teuck has an "enhanced cooling package" or "cooling package upgrade" with upgraded cooling fans among other things. Special heavy duty radiator cost me $700 for the part alone from Chevy(only place that had it)I fixed the fan issue myself with HPtuners. The fans have a low, medium, and high that have a few adjustments, such as RPM and coolant temp. My thought is it may not be an issue with the hardware but rather the software.

@DodDel5-3-6L80e does your truck have the aux fuse block as noted and pictured below

 

[petethepug]

You this or an operating system on a PC set up to run it.

 

[DodDel5-3-6L80e]

@DodDel5-3-6L80e does your truck have the aux fuse block as noted and pictured below
View attachment 449864View attachment 449865

SOrry it took me so long, I will turn on notifications. If that is another box located under the main underhood fuse box- then, no mine does not have that. My truck is not hybred. 8 cillindars all the time as the engineer intened. I ve been thinking of adding another box because Ive piggybacked a couple fuses already. My 12v, while the key is turned to auxillery, fuse choices are very slim.

 

[opfor2]

My Tahoe SSV fans would go on high for no reason whatsoever. Chevy sent me a recall for the fan system. Look yours up, it may be included in the recall. My boarder patrol teuck has an "enhanced cooling package" or "cooling package upgrade" with upgraded cooling fans among other things. Special heavy duty radiator cost me $700 for the part alone from Chevy(only place that had it)I fixed the fan issue myself with HPtuners. The fans have a low, medium, and high that have a few adjustments, such as RPM and coolant temp. My thought is it may not be an issue with the hardware but rather the software.

If I'm not mistaken the recall is for the fan's electrical connections only and requires the installation on new updated connectors for the old stock ones get to hot and melt.

 

[swathdiver]

Cooling fans coming on when not needed

Says you! It's perfectly normal.

The coolant gauge is dampened so as not to fill the service bays with nervous women. If it gets really hot, it'll move in the right direction to warn you.

From the shop manual:

The PCM commands the low speed cooling fans ON under the following conditions:

 Engine coolant temperature exceeds approximately 104.25°C (220°F).
 A/C refrigerant pressure exceeds 1447 kPa (210 psi).
 After the vehicle is shut OFF if the engine coolant temperature at key-off is greater than 101°C (214°F)
the low speed fans will run for a minimum of 60 seconds After 60 seconds, if the coolant temperature
drops below 101°C (214°F) the fans will shut OFF. The fans will automatically shut OFF after 3 min.
regardless of coolant temperature.


The PCM commands the high speed fans ON under the following conditions:

 Engine coolant temperature exceeds approximately 107.2°C (220°F).
 A/C refrigerant pressure exceeds approximately 1824 kPa (265 psi).
 When certain DTCs set.