S14 digital climate control install


Thanks to Russ, Ken, and R&D Factory for the help in figuring all this out. Also, thanks to the guy who sold me everything on eBay.


Took me about 1 week of researching, 2 months of lagging, another 1 week of preparation, and 15-20 hours of mounting/wiring.



Some of the parts below are available off of multiple cars which I will call donor cars. These are:

Required parts

I found this forum post about an Altima DCC install and it looks like all of the parts should work for the S14 so I'm including the Nissan part numbers for Altima (and some Maxima) donor parts. I can't guarantee that all of the parts will work since I haven't tried them. If you've tried them and they work, then let me know and I'll put a note here. The Altima and Maxima parts look the same so as long as they work the same electronically (which I think they do), they should work. There aren't any reserved spaces in the USDM S14 for the parts below (except for the control unit and the sunload sensor), so it won't matter too much if they're not the exact shape and size as the JDM S14 parts. Anyway, the safest bet is to go with a JDM S13 or S14 as the donor since those will work for sure.

Optional parts



Here is a list of the parts that are involved with the climate control system and a description of each part:


Digital climate control (DCC) unit

  1. Push in the bottom of the middle vents and get a grip on that section.
  2. Pull down and out to detach top of the trim from two clips at the top.
  3. Use a finger or a covered flat head screwdriver to pull on the bottom and detach the two clips there.
  4. Pull the trim out and disconnect the plugs for hazard light and rear defroster.
  5. Unscrew the old unit which is attached by four Philips screws.
  6. Screw in the new unit when you're done with all the wiring, plug the hazard light and rear defroster back, push the trim back, and snap in the clips.

Sunload sensor

  1. Use a flat head screwdriver to pry up the windshield vent trim on the seat side (not the window side). There are tabs on this side that are supposed to come up (correct me if I'm wrong). Notice that there's a hole in the passenger side of the main dashboard piece. That's where the sensor sits in. Be very careful because this piece is very brittle in our 12+ year old cars. The trim piece is super fragile! I tried to be careful taking the piece off but all my tabs as well as a couple of the dividers broke off. Below is a picture of the hole in the dashboard
  2. On the bottom side of the vent trim piece, you'll notice there is a hole on either side of the vents. Cut a hole for the sensor on the passenger side hole. The hole is shaped like a circle but with one side flat. Be careful when cutting your hole. I broke my piece in half and then some. I had a partial JDM trim piece that I was able to use as a template for my hole so my sensor snaps in nicely. Below is a picture of the underside of the JDM trim piece to give you an idea of the shape, size, and location of the hole. It is on the opposite site for the USDM piece though.
  3. Run two wires from the DCC unit to sensor location, solder them to the plug, put back the trim piece, connect the plug to the sensor, and snap the sensor into the hole. To run the wires, I fished a wire hanger down the top hole towards the right, over the intake unit and pulled the wire up. Since I broke all the tabs on my trim piece, it just sits there with no support. There's no movement or rattle at all though.

Ambient temp sensor

  1. Run two wires from your DCC unit to your hood latch area.
  2. Solder the wires, plug in the sensor, and mount it. My sensor had a broken mounting tab so I just ziptied it to the hole on the frame support rail. I think there's supposed to be a bracket that attaches the sensor to the frame but I didn't have that.

In-cabin temp sensor

  1. Choose a place to mount the sensor and work with what you have to get it mounted. The sensor is supposed to have a mounting location where the cruise control button is. However, the sensor doesn't fit there and also, if you have cruise control, then you need that location for the button. I didn't include a picture of my setup because I haven't decided on a good place to mount it with good airflow and an accurate reading.
  2. You should have vent holes in front of the sensor to allow cabin air to pass over it so cut some if you mounted the sensor behind a cover.
  3. If you have an aspirator and hose, mount the aspirator onto the front of the heating unit (white box behind DCC unit/radio) and connect the aspirator to the sensor housing with the aspirator tube. I just found the only flat surface on it that would fit the aspirator and attached it with self-tapping screws about 1/2" long. Try to cut the hole nicely so air doesn't leak out.
  4. Run two wires from the DCC unit to your location, solder the wires, plug in the sensor, and finish mounting the sensor.

Fan control amp (AKA blower motor speed sensor)

  1. Make a template so you can cut a hole with the right shape and size to fit the mounting shield into the cooling unit (AKA evaporator) (minus the edges, of course).
  2. Remove the glovebox (two screws at the bottom) and the glovebox frame (four screws around it).
  3. The mounting shield sits on/in the cooling unit (black box on the left behind the glovebox). Cut the hole as far to the left as possible. Vertically, it should be centered on the "equator" on the cooling unit. I used a dremel but it got little pieces of plastic into the cooling unit. I was able to cut some lines with a utility knife so you might want to go that.
  4. Mount the shield onto the cooling unit. (I used self-tapping screws about 1/2" long. I guess you could use glue or double-sided tape but the screws work for me.)
  5. Mount the fan control amp inside the shield.
  6. Run wires according to the wiring section.


The JDM DCC unit has 2 connectors on the back: one with 20 wires and another with 16 wires. The USDM control unit has 3 connectors on the back: one with 12 wires, another with 16 wires, and finally a 6 wire connector for the fan switch. Obviously you won't be able to just plug and play. If you have the complete JDM DCC subharness, you basically just pull out the USDM subharness, lay in the JDM one, plug everything in and go. The only problem is that the USDM air mix door motor's plug is different but it has the same wires so you should be able to just repin it with info from the FSMs. There's probably a little more to it than that but nothing too difficult.

If you're unlucky and don't have the subharness, then you're lucky because you'll have to do a lot of soldering/crimping. What I did was follow the table below, pick a wire to connect, find the wire on the USDM plug, cut it, and attach it to the JDM plug. How you do that is your preference. What I did was crimp on female disconnects to all of the JDM wires, then as I cut the USDM wires, I crimped on male disconnects and partially connected them. This way, if I messed up, I could rearrange the wire connections easily. The crimping took forever and the connectors take up a lot of space and can rattle against things, but I felt more comfortable knowing that I could rearrange the wires without losing wire length due to soldering (desoldering is too much of a hassle).



JDM #JDM colorUSDM #USDM colorPurpose/notes
9 (9)LFS1 and FCA1L and LFAN F/B
11 (1)OR/G12V-BAT
14 (7)B17B-ILL (GND)
16 (2)L/WBM2L/WIGN (+FAN)
20 (7)B17 and FCA3B and BGND
22 (4)L/R1 and 4L/OR and L/WMODE 3
23 (8)G/Y--INTAKE 2
24 (7)(8)Y17BINTAKE 3
28 (8)Y/R--INTAKE 4
30 (4)L/W3 and 6L/R and LMODE 2
32 (8)Y/B--INTAKE 1
33 (6)PAMDM3L/OR+5V (PBR)


Diagnostics mode

This is just a summary of what is in the SR20DET FSM. To enter the diagnostics mode, press and hold the OFF button for 5 seconds within 5 seconds of turning the key to the ON position. You'll start in screen 1 and can go up to screen 2, 3, 4, and 5 by pressing the red UP button. You can go back down a screen by pressing the blue DOWN button.


If you'd like to discuss about this write-up, please visit this Zilvia forum thread.