Nissan Patrol 4x4 (Africa)

Part I - Background and Commencement of Disassembly
I met up with JP on Friday. He had to collect some seatcovers from me, and I'd also promised to take a look at replacing the burnt out back lights on his climate control unit. I'm talking part number 27510-VB011 - as per the unit in the photograph below.
Whilst inspecting the unit he dropped off with me, I also gathered that the recycle / open vent buttons were also sticking a little. Something I looked for specifically, as this is something that happens on my truck too. And something I must fix at some point. I decided I'd give the unit a good going through whilst replacing the bulbs as well...

The back lights are what the call T4 / T4-Tall mounted incandescent bulb. For the LED display back light, the Nissan part number is 275458E100 or substitute part 275458E500. For the button back lights, the part number is 275450N002. Both seem to be exorbitantly expensive - even at PartSouq - coming in at about USD5 per light. The system uses 6 of these, so replacing all the lights with factory standard will rock up to about USD30 for everything. If one gets stock... One gets after market T4 / T4-Tall LED lights, which I might look into at some point. But I'm not at that point yet...

The following schematic from PartSouq shows how it all fits together, but I'll give a walk through of the process.
T strip the unit, one first has to remove the button and LED display backlights. There are four button lights located at the back of the face plate which have white bases, and two LED backlights located on top of the unit with grey bases (highlighted in the next two pictures). Simply use a small flat screw-driver, turn counter clockwise, and the light will come out...
After removing all the lights, the next step is to remove the back cover. Unscrew the four bolts on each corner at the back and then unclip the face-plate from the clips at the top and the bottom of the face plate. All these screws and clips are highlighted below.
Once this is done, the back of the unit will separate a little from the front of the unit. As illustrated in the previous photo. Do not pull the back cover off too far, as we are first going to need to get the circuit board out - it is attached to the front of the unit.

To do this, we unscrew the screws holding the circuit board in place (highlighted below). The circuit board also clips into the back cover itself towards the front of the back cover. Firmly pry the circuit board out of the cover - taking care not to damage it.
Once the circuit board is out, one can disconnect the cable connecting the main board from the front circuit board. Note that the yellow wire on the main board connector must face towards the side of the unit.
This done, we can now strip the front circuit board from the enclosure. Remove the temperature control dial from the front of the unit (it just pulls off). And then remove the three screws holding the circuit board to the face of the unit. Once done, unclip the two clips at the top, the three clips at the bottom and remove the board.
Now, we have access to the back of the buttons. Inspection of these showed that the white silicon grease they use to lubricate plastic parts had, over the years, become very dirty and congealed. I decided to remove everything, give it all a good clean and put it back together again.

I need to edit some photos and run some other errands, so please stay tuned for part II. Cleaning up nice and good and reassembly.

Wow! Awesome work boet & a great addition to the forum's technical pages!

Great stuff not just a pretty face hey..you have skills man

Next installment ready. This is about stripping the final bit of the unit and cleaning everything up properly.

If you've followed the previous steps, you will now sit with the climate control unit separated into the following bits and pices.

1: The removed backlights.
2: Back cover.
3: Main circuit board.
4: Face plate circuit board.
5: Face plate - complete with buttons.

The back of the face plate has two clear plastic light diffusers and the back end of the buttons and looks as below. The light diffusers can be removed simply by pulling them straight backwards. Once this is done, note the orientation of the button guides / inners inside face plate.
Two of these buttons are important as they are the ones that tend to stick. I'll get back to them shortly.

Each button consists of two parts - the outer button (which we see from the front of the unit) and the guide / inner - which is the white plastic thing we see from the back. To remove the buttons is finicky. But before doing so, make a note of which button goes where so that one puts them back in the correct space again at assembly time.

To remove the buttons, press the button from the rear side of the unit forward as far as it will go. Insert a small flat screwdriver underneath the bottom of button (ie: bottom being the bottom of the unit) at the front and gently pry it up. Gently - you do not want to break it. This will release the clip of the button face. The face of the button comes out from the front. Press the white plastic guide bit out towards the back.

The result of this is that the unit will not be completely disassembled.
At this point, we clean everything up. I used normal washing detergent and an old tooth brush to scrub everything clean. Especially the congealed "plastic" lubricant on the button guides.

Stuck Buttons

There are two buttons that seem to get stuck on these units - namely the recirculate and non-recirculate buttons on the top left of the unit. There are several reasons for this - the lubricant congealing with age being one of them. However, inspection of the buttons and the guides show another reason as well.

Unlike every other button on the board, these two buttons are the only buttons where the switch it presses on the circuit board is not towards the middle of the unit. As such, pressing the buttons will always result in the button inner pulling a little skew in it's guides. The points where the buttons connect with the actual switches on the circuit board are highlighted below.
What happens over time is that the inner button guide ribs wear a spot into the cover's guide slots. This means that, when the button is pressed, the guide rib catches in the guide slot and it gets stuck. Using a dremel or a craft knife, carefull cut the guide ribs highlighted below so that they taper towards the back, making sure that the new, cut surface is nice and smooth.
After cleaning everything, use a very slghtly damp piece of kitchen towel to clear the inside the the LCD display on the front cover. At this point, we can start reassembling the face plate. Using a bit of proper plastic lubricant (I used the lubricant they use for plastic runners on garage doors), lubricate the button inners. Not too much - just a smidgen. From there, we reinstall the button guides from the back of the face plate in the same orientation as we noted when disassembling the unit. Place the front of the button over the button guide from the front (in the correct place, naturally) and apply a bit of pressure. The button face will click onto the button guide. At this point, we must remember to put the light diffusers back. They have guides they fit onto, so one can only put them back on in the correct orientation. This done, we can now put the face plate circuit board back on - gently pressing it into the tabs which hold it in place at the top and the bottom edges of the face plate. And we can put the three screws back. Our face plate should now be clean and have working buttons.

The next instalment will be up when I have time. This will deal with removing and cleaning the LCD backlight assembly. After that, I'll get around to getting the lights to work.

Next up - cleaning of the LCD backlight assembly.

I was originally thinking of skipping this step. But considering the age of these specific units, as well as the fact that (in my case at least), I've done a very large section of the sub-continent on dirt road only, and looking at the amount of dust which had accumulated in the unit itself, I reckoned it probably was not a bad idea to get rid of the dust inside the LCD backlight assembly. This is the big-white block thing covering the LCD display.
Very easy to do - remove the screw (highlighted red) and press the two clips (blue) to the side - after which the backlight assembly will come off the board. Note that this screw is larger than the other screws used on the control unit, so keep it seperate.
The LCD backlight section consists of the cover, and a plastic card insert that fits on guides inside the cover directly behind the LCD display. Note that the sides of the card are specific - one side is clear, and faces the LCD. The other side has shading on it to allow even light distribution behind the LCD.
Clean well with washing detergent and water, and rinse. When dry, clean the "card" section of the assembly with a very slightly damp kitchen towel. Also clean the LCD screen perpendicular to the main circuit board with the kitchen towel. Ensuring that the backlight card and LCD screen are properly inserted into their guide slots, clip the cover assembly back into place and replace the screw.

At this point, we can reassemble everything. Align the main circuit board's pin connectors with the corresponding sockets and press them in. Reconnect the control cable (remember - yellow is to the side). Align the slot in the back cover with the main circuit board and press it all together. Replace the four screws holding the cover to the front plate, and the two screws holding the circuit board to the back cover.

We now have a complete, clean control unit with working buttons.

Next instalment up: the replacement backlights.

Right. Back to the lights. As per the first post on this subject, the factory standard lights are 12V incandescent bulbs. They are covered in blue film - presumably to counter the "yellow" light produced by the bulbs. ie: So that the console back light has a nice "blue" glow.

I opted to replace the incandescent bulbs with LED's, making use of 3mm white LED's with a 510 ohm ballast resistor on the annode. I used the existing bases, removing the original bulbs by twisting the wires out of the connection slots, and then pulling the bulb out from the front. I drilled out the one side of the base with a 2.5mm drill bit to accommodate the resistor before sticking the bulbs in place using epoxy.
One caveat here is the following - if you recall in the first post, I mentioned that two different types of bulbs are used. T4 and T4-Tall. The T4-Tall fittings are long eough to accommodate the resistor inside the base of the light. The photos shown here are the standard T4 bulbs. This means that the resistor sticks out behind the base. However, I've just nicely shrink-wrapped the exposed resistor. I've had another cunning plan I'll get to shortly.
LED's differ from conventional bulbs in several ways - including the fact that polarity is important. At this point, I had measured polarity on the actual control unit, so to test that everything was working, I temporarily connected the lights to a 12V source in-situ. The results are good. :)
In the meantime, I've come up with a cunning plan to make the bulb bases more LED friendly, so I designed a few bases of my own and printed them out on my 3D printer. This specific example if a T4-Tall base. With the T4 bases, I have a lot more room to play with as the bases connect to the control unit from behind the unit. As such, I will be making them such that the bottom of the base is much thicker and can comfortably accommodate the resistor.

It was eventually time to test the unit in the really-real world. I stripped the dash of my vehicle and, with my climate control unit still installed, I measured the polarity of the sockets with a multimeter.

For the button back lights at the rear of the unit, the polarity is as follows (note: this is looking from the rear of the unit):
For the LCD backlights at the top of the unit, the polarity is as follows:
I refitted the LED's according to the polarity, removed my climate control unit from the truck and plugged in the replacement one. Voila.
All in all, I'm very happy with how it all turned out. I think things will be easier with the new bulb bases I am printing currently. And hopefully this solves somebody else's issue one day. Thanks for reading. :

fook mi !!!

Anthony Forgey wrote:fook mi !!!

Nope...

Fook yoo !!!

Just joking. Hope it helps. Let me know if you need bits and pieces... :)

I am very excited about this!!!

Thanks again Ian!

Very well presented dude...