Only blows defrost cannot switch from hot to cold

Tiny
JOSEIZ19
  • MEMBER
  • 2016 JEEP PATRIOT
  • 4 CYL
  • 4WD
  • AUTOMATIC
  • 98,300 MILES
When I start the vehicle the defrost button blinks for a few minutes and when it stops it starts only blowing hot on defrost only even though the settings are on max A/C and max cold and the setting in which the A/C is supposed to be blowing towards is on the face forward it still keeps blowing hot air out the defrost eventually everyone and then it’ll actually work, but it always goes back to messing up. What do I do to fix it? Please help.
Sunday, June 14th, 2020 AT 9:20 PM

2 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,141 POSTS
Sorry to have to tell you, but the computer needs scanned. The blinking light indicates a fault in the HVAC system. You need to have an actuator DTC detection test completed that requires a scan tool which can read HVAC codes. Although most parts stores will scan for free, they don't have the ability to check these types of codes.

I wish I had a better answer, but there are multiple things that can be causing this to happen.

Let me know if you have other questions.

Joe
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Sunday, June 14th, 2020 AT 10:25 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,141 POSTS
Hi,

Just to add a thought. The type of scan that is needed can be done by most shops. What I suggest is to scan the CAN BUS system. Here is a quick video that shows how it is done:

https://youtu.be/InIlnsjOVFA

I hope this helps.

Joe
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Monday, June 15th, 2020 AT 6:47 PM

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