I did order the ATC panel from ebay, it is used but it's in really good condition. However, it did not come with the connectors that goes into the back of it. I'm probably going to head to my local u-pull-it yard, and I was wondering if I could possibly just grab the whole wiring harness? Also, should I buy a new sunlight sensor or grab a used one? (they're quite affordable new) I will be doing the rear HVAC panel later. I have to mess with a blend door in the rear AC unit because it currently sounds like a faint whistle, and my van fails the blend door auto-check because of said blend door.
For the sunlight sensor connector, would I have to tear down the dashboard to get to it, or does the panel at the very top of the dashboard come off by itself? (with the speaker grills on it)
Also, if it wouldn't be possible (or recommended) to grab the whole wiring harness for the front HVAC system, where could I find accurate diagrams to re-pin the old wires into the new connectors? I can get the new connectors online from what I saw, but I feel that getting the whole harness from a local yard might end up being cheaper, or the same price, as ordering those.
You do not have to re-wire the dash for the auto panel, but I'm sure you can if you really wanted to. It's just a lot of unnecessary work and that time could be spent on better things. You only have to run 2 wires, both go to the sun sensor which sits just rearwards of the center speaker hole, your van has a cap there. You can buy a new one if you so desire but I've never had a used unit fail. One thing to keep in mind, make sure the sun sensor itself has 4 actual pins inside of it, not 3. Only other notable thing is when you go to re-pin the MTC pins into the different shape ATC connector, one of the MTC connector pins has this tab which extends out and prevents them from sliding into the new ATC connector. Grab needle nose pliers and fold that piece which extends out, to be flush with the pin and then it will slide in, and clip into the atc connector perfectly. It will still fit back into the MTC connector should you want to go back.
I'd prefer to have the instructions to tear down the dashboard, in preparation for when I do decide to do the EVIC cluster upgrade. I'm pretty sure I also need the compass module for the compass feature to work. I'll study into all of that a bit more down the line after I recoup some of my money from the lovely alternator job.
From what I've studied, the center bezel that contains the climate control is pretty much just clips and two bolts/screws hidden behind the head unit bezel, so I should
be fine there. But, I'd also like to find a diagram for how the AC harness is laid out in the dashboard, if I decide to just grab a harness with the ATC connectors already on it from the salvage yard.
The EVIC swap is simple for 2011+ vans. Swap the cluster (but you have to remove the dash pad which is a fair amount of work), and you add the compass module (connector is already in the dash, you should be able to reach it from the footwell or the center speaker hole), and then you must swap the left steering wheel switch. Programming change "compass module present to "set", and premium TPMS to "Set" which will then display all the tire pressures (but not in the correct position). That should be it for EVIC.
The center bezel is easy to remove. First remove the bezel around the radio, it pries straight out, then there's 2 Philips screws just above the air vents, remove them and push the top of the entire center bezel out, may remove the radio to make it easier. Then just pull it straight out and disconnect the connectors.
I do not recommend swapping the entire dash harness, but it's completely up to you. Book an entire day for it if you do decide to swap it, and work slowly. Remember the HVAC ductwork in the dahs bolts to the inside dash frame, take your time and don't force it.
Edit; the only options to add for the dash harness itself are the power inverter for the rear, if it's not already equipped (but may be wired already), and the auto climate controls with the different connectors, and the premium sound system with the amplifier but it's more tearing apart then just the dash. If you are talking about adding any of the following; backup camera, overhead screen(s), bluetooth, or dvd player that is all a separate harness which sits in the dash. It can be pushed and pulled through the gaps above the air vents below the plastic dash frame without any more removal other then the radio, center bezel, passenger glove box, and A-pillars.
Here's what the entertainment harness looks like which sits in the dash;