Electrical issue with climate control

[CM_Ram13]

Hi everyone, I’ve searched this site extensively and asked dealers, mechanics, and parts places and nobody seems to know. Hopefully someone might have a thought on this. I’m thinking electrical but don’t know what wires to look for.

I have a 2013 Ram 1500 SLT, V8 5.7l engine. Bought it in 2018 with barely any heat working. Everything is stock on the engine - no modifications to anything I’ve changed listed here. *Single zone climate control* I can’t tell you how many people have asked if I’m sure it’s single zone.

So far, I’ve changed heater core and evap core, replaced blower motor resistor, flushed radiator, changed radiator cap, burped the engine and radiator countless times to ensure no air pockets, and pulled the fuse box out from under the hood and checked all connections underneath to ensure no corrosion. Fuses are all good, I have continuity through the climate control fuse. All blend doors work as they should, all actuators are intact and work correctly. I know the thermostat is functioning properly - the coolant temp sensor reads 212° when it opens then cools to about 194-198° while driving. Both hoses to heater core at burning hot when the engine is hot.

The first thing that is odd: The AC compressor comes on every time the climate control is turned on. If I turn either heat or AC on, the AC compressor automatically kicks on. I have to manually turn it off by pushing the middle knob on the climate control. Also there is no reset to the climate control, I’ve tried to too many times and nothing happens.

If I get in and drive for any amount of time, whether it’s 15 minutes or 3 hours, I don’t get heat. I get outside air temp plus 20° so it blows warm when it 50° outside but blows ice cold when it’s zero degrees.

It gets weird here: the scenario is I get up to normal operating temp and the thermostat opens. If I get out and lock the doors and wait 5-10 minutes (when I go to get a coffee) then unlock and get back in, it blows perfect hot heat on the coldest days (this works every time I’ve tried it). BUT if I don’t lock it then unlock it, it doesn’t blow heat, or doesn’t if I do it too quickly. And I can’t just sit in the truck for 5 minutes with it off either. I’m guessing there’s some electrical issue somewhere but have no idea.

It’s a lot to take in but I figured I’d list everything I’ve done because I know I’ll get a bunch of “did you try this?” answers.
Thank you in advance

 

[NETim]

Just for clarification, your truck has the auto climate control single zone mod installed, right? Someone has updated it somewhere along the line. Hopefully both the temp and the humidity sensors were installed. My understanding is that both are necessary.

I would try the auto climate install process again via Alfaobd and see what happens. Just feels like a s/w issue rather than a hardware issue to me.

 

[Mpgrimm2]

What HVAC module part number do you have behind the passenger side air vent?
(Should be 68105017Ax)

Wyatt's your VIN?

 

[Jeepwalker]

You might type your vin into the Chrysler site and bring up your truck's options it came with, like said above, in case someone tried a half-hearted conversion.

I'm trying to remember how the return air/outside air damper is situation on that truck. Did you ensure the return & outside air damper door/actuator are working properly. If a damper door weren't closing all the way, and cold air was back-flooding into the cabin, the heater couldn't keep up. Might not be your problem, but Ive seen it.

Another problem 'could' ...if the controller is the correct one and the outside air damper was right, it's entirely possible the controller ground isn't good. You DO live in the salt-zone. Check the grounds above the front pass tire, and the battery-to-body grounds are real good. There are ground wires from the harness around the inside of the cabin too. It's hard to check them, but if you get to the point of replacing the controller, consider making/running a ground wire from the controller itself to a metal portion of the body. Just to rule out bad grounds so you don't have the same problem with a new controller.

 

[CM_Ram13]

Just for clarification, your truck has the auto climate control single zone mod installed, right?

I would try the auto climate install process again via Alfaobd and see what happens. Just feels like a s/w issue rather than a hardware issue to me.

Its turn knob application but automatically (electrically) opens and closes the blend doors.

I’ll have to look into the alphaOBD and test that out

 

[CM_Ram13]

You might type your vin into the Chrysler site and bring up your truck's options it came with, like said above, in case someone tried a half-hearted conversion.

Hadn’t thought of that. It was originally a fleet vehicle in Canada so I’d assume it was well kept. Though I have contacted dealers asking about several parts based on part numbers that are in my truck, and they claimed at least three parts I have won’t fit my VIN - they supposedly only fit other models and years so I could never understand that

Did you ensure the return & outside air damper door/actuator are working properly.

Yes. It opens and closes and seals shut both ways.

It's entirely possible the controller ground isn't good. You DO live in the salt-zone. Check the grounds above the front pass tire, and the battery-to-body grounds are real good.

I thought the same thing and did check those main ones. But I didn’t know if there was any specific one ground wire that might be more likely to cause an issue with climate control.