Heater issues

Zaythedad

Zaythedad

Member
Joined
Apr 27, 2020
Messages
36
Location
Pueblo, Colorado
Okay I so purchased the 13 JK in summer. Heater seemed fine but that was dead summer as well fast forward to this week Colorado was dumped on with snow and I needed to use the heater boom issue number 1:

heater will only blow kinda warmout of passenger side vents and cold out of driver side.

so I watched this:


I think I have that as a solution went to dodge this morning and bought OAT high image purple thanks Chris for that btw.

Now I opened my hood this morning checked my tubes and notice the two black tubes to the core are warm to the touch. Not terribly hot but warm and the pipes the metal ones are hot hot. So after fiddling with them my heater inside has just gotten warm for the last hour. But the moment I switch it to defrost to get rid of fog it goes cold on one side AGAIN then I have to swap it to front facing with it recirculating air to get it kinda warm again.
Worried to take it to dealer ship to see and get the same answer everyone I read online has gotten and it keeps coming back for them.
Would love some input fellas

Sorry for the long long post and the random periods my phone is kinda trippy sometimes.
 
So you didn't flush the heater core? Cold air on drivers side is a big indication that the heater core needs a flush. The sludge the guy shows is more than enough to keep it from getting super hot. The same thing was happening on mine, flushed it and captured what came out. Didn't look like anything did, but heat works great now.

The problem the guy ran into was that he didn't get the air out of the system. Bleeding the system is really the hardest part of this operation.

The other thing you might try is with the Jeep off, turning the HVAC knobs all the way to the left, pull J15 for 10 seconds, replace the fuse, then start the engine. I used to have to do this on my 14 to get the actuator doors into the default position on occasion.
 
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MacGuyver said:
So you didn't flush the heater core? Cold air on drivers side is a big indication that the heater core needs a flush. The sludge the guy shows is more than enough to keep it from getting super hot. The same thing was happening on mine, flushed it and captured what came out. Didn't look like anything did, but heat works great now.

The problem the guy ran into was that he didn't get the air out of the system. Bleeding the system is really the hardest part of this operation.

The other thing you might try is with the Jeep off, turning the HVAC knobs all the way to the left, pull J15 for 10 seconds, replace the fuse, then start the engine. I used to have to do this on my 14 to get the actuator doors into the default position on occasion.
Click to expand...


So your saying the computer talks to the heater also?
 
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BLACKJKU said:
So your saying the computer talks to the heater also?
Click to expand...
I don't know about a computer or if there is a processor on the hvac board, but the hvac controller definitely performs a calibration.

The fact that the heater core hoses don't get hot lead me to suspect an air pocket, or maybe blockage. Is the temp gauge reading normally? Thermostat could be stuck open, too.

I feel for you dealing with heat issues when it gets cold. No fun!
 
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MacGuyver said:
So you didn't flush the heater core? Cold air on drivers side is a big indication that the heater core needs a flush. The sludge the guy shows is more than enough to keep it from getting super hot. The same thing was happening on mine, flushed it and captured what came out. Didn't look like anything did, but heat works great now.

The problem the guy ran into was that he didn't get the air out of the system. Bleeding the system is really the hardest part of this operation.

The other thing you might try is with the Jeep off, turning the HVAC knobs all the way to the left, pull J15 for 10 seconds, replace the fuse, then start the engine. I used to have to do this on my 14 to get the actuator doors into the default position on occasion.
Click to expand...

Have not flushed yet taking it to mechanic tomorrow. To see maybe if they have and idea but hopefully a flush is in the future to help.
 
JerryD said:
I don't know about a computer or if there is a processor on the hvac board, but the hvac controller definitely performs a calibration.

The fact that the heater core hoses don't get hot lead me to suspect an air pocket, or maybe blockage. Is the temp gauge reading normally? Thermostat could be stuck open, too.

I feel for you dealing with heat issues when it gets cold. No fun!
Click to expand...

Temp gauge is running center no issues. I noticed when I do recirculating air it gets slightly warm but today is the only time this had happened with is getting a little warmer. But the hoses aren’t completely cold either they are warm but not hot like I thought they should.
 
Yep, sounds like you need a heater core flush or you have an air pocket. Both cheap, easy fixes, and the place to start with a JK.
 
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