A/C evaporator freezing up after 50 min. on the highway

[cybor462]

Hi all

 

Well just recently bought my first GM pickup ever. Got the 2016 Colorado in Oct 2016 and today it has 2500 total miles. Just had it on the highway for the very first time last week and with 95* temps with 85% humidity after about 50 miles on the highway the evaporator froze up and of course it stopped blowing cold air. The return line under the hood totally froze up with 1/2 of solid ice covering the entire metal part of the line. I shut the A/C compressor off and the line melted and also turned the blower to highest setting which thawed the evap and of course it was like have the garden hose on their was a stream of water coming from the evap drain for a good 5 min as it thawed. After it thawed I turned the A/C back on and it worked just great.

I took it to the dealer. I wont go into all the garbage I had to deal with but after 3 days they said they put in a new evap sensor and it was fixed. The last I knew you have to rip the dash apart to get at the evap box and they did it in 30 min. I asked them and they said there is an access area to the switch by the gas pedal and no dash removal needed. I bought it until I was on the highway again today and the exact same thing happened.

 

So my question to any techs reading this.....is there an access area on the hvac box to replace the evap sensor in 30 mins or did they just give me the shine-on? It did not fix the issue.

 

Thanks

[Andris8]

Ask your dealer for the service bulletin on the air conditioning issue. I took mine in the other day for the same thing. They handed me the service bulletin and told me they can't fix it. They said GM has not come up with a fix and won't pay them to work on it. My truck is new with 2500 miles on it. I emailed GM and I am calling them on Monday.

[newdude]

Evaporator temperature sensor isn't part of the evaporator per say. Its accessed via the left side of the blower box (to the right of the gas pedal) where the evaporator sits in the box. Take it back and tell them to keep it until they can duplicate your problem and fix it.

 

Have your dealer find this PI bulletin from GM: #PIT5525: Poor Air Conditioning Performance Above 80 Degrees F --27 C - (Nov 1, 2016)