Radiator Fan stuck on Hi and A/C not working after batter disconnected 2014 Tahoe - Not Temp Sensor or Thermostat

[Stock-ish]

I have a 2014 Tahoe LS, recently disconnected battery and also changed driver side head light. Other than that, Fan was operating normally and A/C worked prior without issue. Now, Coolant fans come on Hi after a minute of being started and A/C blinks 3 times when pushing snowflake button or the recirculating blinks three times when you try and select it as well.

I have changed the temp sensor with Genuine GM part, although the other seemed to be working fine. I had borrowed a Bidirectional scanner and can not see anything in the live data that would indicate an issue.

From what I have gathered, this is most often a bad Temp sensor or MAF issue. Both seem to be operational in live data. There is no CEL, and no codes are pulling when scanned and vehicle health check everything returning ok.

I have tried disconnecting battery overnight, resetting the HVAC system, pulling HVAC fuses and relays to ensure no corrosion build-up. I am at a loss for what it could be at this point.

I confirmed the Thermostat was opening and closing in the live data feed, being that our temp gauge doesn’t really fluctuate in the needle when reaching temp. I was able to perform actuation tests in the scanner and manually turn off the fans, but A/C still won’t come on. Seeing if anyone else here may have anything else that they have experienced that may could be the culprit.

 

[j91z28d1]

edit.. ha you said you borrowed a bidirectional scanner.

try commanding the fans off and see if they shut down

 

[j91z28d1]

you can try the old trick of not just taking the battery cables off, but touch them together for a bit too. that drains the caps and from other threads seems to reset the havc enough that the blinking light goes away.

 

[Stock-ish]

edit.. ha you said you borrowed a bidirectional scanner.

try commanding the fans off and see if they shut down

Yes, I tried that and they did indeed shut off.

 

[Stock-ish]

you can try the old trick of not just taking the battery cables off, but touch them together for a bit too. that drains the caps and from other threads seems to reset the havc enough that the blinking light goes away.

Tried pressing horn first and then did as you suggested for about 10 seconds before connecting back.

 

[petethepug]

Did you knock the harness off the overflow tank by the battery when you were in there?

 

[Stock-ish]

Not that I am aware, but I’ll check in the morning to be sure.

I also am charging the battery with the NOCO Genius 5 just to be sure it isn’t the battery. Leaving it disconnected overnight and charging to see what happens. It shouldn’t be, as it’s only over a year old, but couldn’t hurt.

 

[Foggy]

I would bet that you have air in your coolant system. Get on flat ground or just
point up hill a bit... Leave off your coolant pressure tank cap and let it
idle with both heat settings to full hot and blower medium ish
If it gets too hot, turn it off and let it puke and cool for a while...
You'll know when you get it done...
By changing the temp sensor on the front of the drivers side cyl head, air
was introduced into the system

 

[Doubeleive]

might be worth a try to check, clean and reseat the ecm/pcm harness and maybe the fuse box also.

 

[Stock-ish]

Ok, so I suspect it is the battery. I recharged it with the NOCO overnight and tried to run a repair cycle just to restore any power lost through sulfating. It would not go into repair mode. I tried about ten times reseating the clamps and power cycling, it just would not start the repair cycle.

So with a fully charged battery according to the NOCO, I noticed that the entire 35 mile drive to my dad’s this morning the alternator was charging at around 14 amps the whole time. If the battery had just been freshly charged, it should not have stayed charging that long.

I came to use my dad’s shop today so I could replace front end links, front struts, and rear shocks. While I was her we got to talking about the issue, and he said he had issues with my grandpas truck doing all kinds of crazy stuff and it turned out the battery needed to be replaced. He said it always started fine, but would throw random lights and the CD player would go haywire. When he said that, I was almost certain that is the issue as my CD player freaks out randomly and says ejecting when no cd is even in it.

I don’t have a battery tester, but I am getting new tires installed Tomorrow and will have them test the battery while I’m there, but I’m pretty sure that’s the issue.