Radiator Fan Issue

[c6Vette05]

I have searched the forums for the past few days, and google as well, only thing kind of close is this thread but it isn't quite the same: https://www.tahoeyukonforum.com/threads/electric-radiator-fans-running-more-than-usual.84960/

I have a 2011 Tahoe 5.3 LT 2wd with towing package. Now that it is hot here in Phoenix, when I turn on the car and the AC is on (AC and recirc), the left fan runs at really high speed while the right fan doesn't. The battery gauge reads just past 14 V. When I am driving, the right fan kicks on, I see the battery gauge drop down a bit, below 14 more like 13 or so. I pulled over and checked and the right fan was on, when it turned off the battery gauge went back to normal. I did not have a multi meter with me at the time.

A, is this normal?
B, is it a fan motor issue or an ECU issue?

C, not sure if it is related or not, but the AC does get hotter (up to 48 degrees) and humid for less than a minute (I timed it) occasionally and then goes back to blowing 38 degree air (measured with digital thermometer). These measurements were on a 104F degree day. Yesterday at 109F driving home for 40 minutes, it did this cycle only 3 times.

Thanks for any help!

 

[Doubeleive]

as far as I know it is normal for one fan to kick on higher than the other depending on the given situation I believe the ac system is cooled more on the right side, there is a known issue for some fans to cause the harness to get hot and melt the harness but I believe it was for very specific vehicles and it was a recall (or TSB) which involved just replacing the harness connector, but you could always check with your local dealer just to be sure if yours is in that range of vehicles or not.

 

[Big Mama]

Agreed on the fan and you can go to nhtsb website to see recalls and complaints

 

[mikeyss]

I was a GM tech and can tell you, this is Not normal. They both run at the same speed at all times. If they are commanded on low, both are on low. If commanded on hi, they both run on hi. However, if you use a tech2, you can command one fan to go on hi and the other on low, it's sort of a relay test. Replace your fans, especially where you live, you'll overheat at some point.

 

[gpracer1]

What mikeyss said, and don’t worry about the volt meter. I’m also in Phoenix and on full blast on a hot day the voltage can go down to 12.5 or so which looks really low on the gauge. I’m guessing the ECU is trying to not boil the AGM battery at those high ambient temps.

However if both fans run, you could replace the relays first and cheaper diagnosis.

 

[Doubeleive]

I was a GM tech and can tell you, this is Not normal. They both run at the same speed at all times. If they are commanded on low, both are on low. If commanded on hi, they both run on hi. However, if you use a tech2, you can command one fan to go on hi and the other on low, it's sort of a relay test. Replace your fans, especially where you live, you'll overheat at some point.

maybe because mine are a 7/9 blade it just sounds like one is running faster than the other, thought it might be normal otherwise. when I upgraded mine I put brand new motors on so must just be my imagination, lol

 

[c6Vette05]

Thanks everyone and especially mikeyss. I will get new relays tomorrow (just found out the parts numbers and will call the dealerships to see if they have it). The current relays look find but for $25 or so it might be worth trying. If that doesn't fix it then I will get a new fan motor. Luckily I have an older Pathfinder I took out of storage while I am getting the Tahoe fixed up so it is not being driven around.

 

[BG1988]

I have searched the forums for the past few days, and google as well, only thing kind of close is this thread but it isn't quite the same: https://www.tahoeyukonforum.com/threads/electric-radiator-fans-running-more-than-usual.84960/

I have a 2011 Tahoe 5.3 LT 2wd with towing package. Now that it is hot here in Phoenix, when I turn on the car and the AC is on (AC and recirc), the left fan runs at really high speed while the right fan doesn't. The battery gauge reads just past 14 V. When I am driving, the right fan kicks on, I see the battery gauge drop down a bit, below 14 more like 13 or so. I pulled over and checked and the right fan was on, when it turned off the battery gauge went back to normal. I did not have a multi meter with me at the time.

A, is this normal?
B, is it a fan motor issue or an ECU issue?

C, not sure if it is related or not, but the AC does get hotter (up to 48 degrees) and humid for less than a minute (I timed it) occasionally and then goes back to blowing 38 degree air (measured with digital thermometer). These measurements were on a 104F degree day. Yesterday at 109F driving home for 40 minutes, it did this cycle only 3 times.

Thanks for any help!

Needs more Engine Fan Fluid!





my does it with remote COLD start.. Perfectly normal if you are that worried keep an eye on the temp gauge should be a 1-2mm passed the middle.
it had been about 100F outside the passed few days.. mine stays at 15Volts (14.8 but rounds up to 15volts)

that is includes the dual A/C system ON

but it is a High Voltage Direct Current to 12+VDC step down. 185amps


i can check tomorrow it's going to be like 97F

 

[c6Vette05]

Needs more Engine Fan Fluid!

View attachment 225193



my does it with remote COLD start.. Perfectly normal if you are that worried keep an eye on the temp gauge should be a 1-2mm passed the middle.
it had been about 100F outside the passed few days.. mine stays at 15Volts (14.8 but rounds up to 15volts)

that is includes the dual A/C system ON

but it is a High Voltage Direct Current to 12+VDC step down. 185amps


i can check tomorrow it's going to be like 97F

Doh, engine fan fluid, how could I have missed that!

On another note, the problem has been solved. Replaced all 3 radiator fan relays and both fans now turn on/off in sync. Outside inspection of the old relays shows no signs of damage, wear or melting.

Thank you mikeyss!

 

[mikeyss]

I'm glad you fixed it.

I meant to reply to this the other day....mine sound the same on both sides. Only difference mine may have than yours is that I have the later style K5L dual 700W 5 blade no rim fans. They are louder than my 05 fans that have a rim around the blades.