03 Liberty heat stuck on all the time

[kj705]

The previous owner said that his mechanic told him it would be cheaper to just put the heat on all the time (it was either no heat or heat on all the time). It's summer and hot so looking to fix it. Basically, the temperature doesn't change (heat is on 24/7) and the mode won't change (on defrost) but can change the fan speed. Is this an issue with the blend door/blend door actuator or could it be something else? Thanks!

 

[exacerbated]

I offer my naivete only to break the radio silence. Maybe my vast ignorance will inspire others to actually help.

I think the air-hole selector (panel, floor, defrost, etc) is vacuum powered. The mechanic may have disconnected the vacuum lines and capped/plugged upstream of a leak. Or maybe the selector itself is the leak.

Regarding the cool/heat, I had that happen on a non-Jeep I used to drive. The plastic gear on the blend door actuator broke. It was an easy swap on that particular vehicle. Individual results will vary.

 

[klc]

There are some posts here about this. I’m trying to find it in the Service Manual, but here’s the extract.

Post in thread 'heater & ac'
https://www.jeepkj.com/threads/heater-ac.62356/post-718575

 

[kj705]

I offer my naivete only to break the radio silence. Maybe my vast ignorance will inspire others to actually help.

I think the air-hole selector (panel, floor, defrost, etc) is vacuum powered. The mechanic may have disconnected the vacuum lines and capped/plugged upstream of a leak. Or maybe the selector itself is the leak.

Regarding the cool/heat, I had that happen on a non-Jeep I used to drive. The plastic gear on the blend door actuator broke. It was an easy swap on that particular vehicle. Individual results will vary.

I offer my naivete only to break the radio silence. Maybe my vast ignorance will inspire others to actually help.

I think the air-hole selector (panel, floor, defrost, etc) is vacuum powered. The mechanic may have disconnected the vacuum lines and capped/plugged upstream of a leak. Or maybe the selector itself is the leak.

Regarding the cool/heat, I had that happen on a non-Jeep I used to drive. The plastic gear on the blend door actuator broke. It was an easy swap on that particular vehicle. Individual results will vary.

You must be registered for see images attach

I took the dash out, got to the actuator and found this. Installed a new actuator and plugged in controls to test and the hvac fan speed turns on the rear wiper…what’s going on?

 

[exacerbated]

Does the HVAC fan speed control the fan speed?
Or just the rear wiper?

Looks like you're on the hunt for an electrical Gremlin... (Two points for Captain Obvious here. That's me. I just earned two points.)

You must be registered for see images attach

 

[exacerbated]

I'm no computer **** kid, but it looks like maybe both A/C Control and Rear Wiper Control are routed through Body Control Module at Connector C1.
Maybe disconnect that bad boy, clean it up, and see if everything looks kosher?

Service Manual
page 1014 BCM C1 pinout
page 1113 BCM C1 location
page 903 rear wiper ckt. See center of page for BCM C1 pin 13 Rear Wipe Wiper On
page 902 A/C ckt. See center of page for BCM C1 pin 24 A/C On/Off Control

 

[kj705]

I'm no computer **** kid, but it looks like maybe both A/C Control and Rear Wiper Control are routed through Body Control Module at Connector C1.
Maybe disconnect that bad boy, clean it up, and see if everything looks kosher?

Service Manual
page 1014 BCM C1 pinout
page 1113 BCM C1 location
page 903 rear wiper ckt. See center of page for BCM C1 pin 13 Rear Wipe Wiper On
page 902 A/C ckt. See center of page for BCM C1 pin 24 A/C On/Off Control

Thanks! I'll take a look at that. I noticed when I hooked up the new blend door actuator and turned the switch- the gear didn't turn. Guess I have to track that down too!

 

[exacerbated]

I'm sure you already followed or referred to the blend door actuator calibration that klc referenced above?

Let us know what you find!

 

[kj705]

I'm sure you already followed or referred to the blend door actuator calibration that klc referenced above?

Let us know what you find!

I did try to calibrate it, still nothing. Still confused how swapping out the blend actuator made the fan speed turn the rear wiper on. I also don't have power getting to the connector that goes to the blend door actuator...not sure where to go from here

 

[exacerbated]

Are Junction Block C1 pins 28 & 29 hot with key in RUN position? (Ref page 883)
Is Fuse 25 at Junction Block C1 happy? (Ref page 883)

If it were my car, I might swap the A/C Control with a junkyard part. They cost $25 from the yard and $60 if you can find it on eBay? I know it's throwing money at the Jeep without a proper Differential Diagnosis. Hence my username & tagline under the user name?

A more careful read of the wiring diagrams might reveal additional crossovers & short location candidates besides the Body Control Module C1. That was just the obvious shared connector for Fan Speed & Rear Wiper. But tying to the blend door actuator is more difficult. Looks like it goes straight from Junction Block to the Actuator without going through one of those giant connectors.

But again, maybe I just made it worse!

 

[kj705]

Are Junction Block C1 pins 28 & 29 hot with key in RUN position? (Ref page 883)
Is Fuse 25 at Junction Block C1 happy? (Ref page 883)

If it were my car, I might swap the A/C Control with a junkyard part. They cost $25 from the yard and $60 if you can find it on eBay? I know it's throwing money at the Jeep without a proper Differential Diagnosis. Hence my username & tagline under the user name?

A more careful read of the wiring diagrams might reveal additional crossovers & short location candidates besides the Body Control Module C1. That was just the obvious shared connector for Fan Speed & Rear Wiper. But tying to the blend door actuator is more difficult. Looks like it goes straight from Junction Block to the Actuator without going through one of those giant connectors.

But again, maybe I just made it worse!

Help!! So confused...plugged cluster, airbags, window switches and even radio in to see if that helped and now my cluster is lit up like a Christmas tree (no key light, airbag light, oil light, and check engine light) the radio screen doesn't work (no time...just cycles thru the cd changer). None of these were issues before. Any ideas?

 

[exacerbated]

That's crazy. It ***** when you try to make something better and it just gets worse. Been there.

I'm stumped. Hopefully smarter kids that I will chime in.

I wonder if doing a quick ECU reset is worth it. It's *almost always* harmless. I would say "always", but I'm shy on universal statements and hyperbole.

 

[DadOSix]

How far apart did you take the dash?

 

[kj705]

That's crazy. It ***** when you try to make something better and it just gets worse. Been there.

I'm stumped. Hopefully smarter kids that I will chime in.

I wonder if doing a quick ECU reset is worth it. It's *almost always* harmless. I would say "always", but I'm shy on universal statements and hyperbole.

I removed the battery terminals and zip-tied them together, turned the headlights on to drain anything left waited 10 minutes and voila everything reset and fixed itself haha shout out to scotty kilmer

 

[kj705]

seems like blend door actuator still isn't working correctly...ill try to calibrate now

 

[kj705]

How far apart did you take the dash?

everythings out, plugged in one of those a/c rechargers to see if i can get cold air and this is what its reading

 

[DadOSix]

everythings out, plugged in one of those a/c rechargers to see if i can get cold air and this is what its reading

So with the whole box out of the jeep, when you re-assemble, the a/c lines need to be drawn down with a vacuum pump so there is enough volume for the refrigerant. If you did not evacuate the system, there is nowhere for the 134a refrigerant to flow. That said, if the system was open to the atmosphere, do yourself a favor and change out the receiver drier then pump it down. Add some a/c oil, and recharge it. If your refrigerant is too low (nil), the clutch won't operate. Marginal charge lets the compressor fast cycle - lots of on and off at the compressor clutch.