Rear AC fan speed control repair

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pgreeff
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Full Name: Paul Greeff
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Current 4x4: 2004 Nissan Patrol 4.8
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Rear AC fan speed control repair

Post by pgreeff »

Some months ago I noticed the rear AC doesn't appear to work.

This weekend I opened up to look for the problem.

Symptoms
Rear passenger airconditioning unit blower fan only works on setting 4 of 4. Speeds 1, 2, and 3 the blower fan remains off. AC unit works just fine on speed 4, with nice cool air.

Locating the problem
Bottom trim inner panel removal.
Bottom trim inner panel removal.
IMG_20201227_133909.jpg (753.75 KiB) Viewed 377 times
The aircon unit is hidden under the left rear trim of the Patrol. After removing the smaller panels it was obvious all the trim will have to come off.

It seems the best way to remove the panels would be to start from the top and remove the upper plastic portion first. I thought it might be possible only remove the bottom half, but it is attached at the top with clips hidden from view under the plastic panel.

Bottom trim seat belt removal.
Bottom trim seat belt removal.
IMG_20201227_134039.jpg (3.35 MiB) Viewed 377 times
Seatbelt removal. Both the third row and second row seatbelts will have to be removed for the whole panel to come out.

Bottom trim loop removal.
Bottom trim loop removal.
IMG_20201227_135325.jpg (680.83 KiB) Viewed 377 times
Upper trim handle removal.
Upper trim handle removal.
IMG_20201227_140708.jpg (655.65 KiB) Viewed 377 times
Bottom trim last clip.
Bottom trim last clip.
IMG_20201227_140955.jpg (768.84 KiB) Viewed 377 times
Bottom trim last clips.
Bottom trim last clips.
IMG_20201227_140958.jpg (1.13 MiB) Viewed 377 times
Bottom trim clip removal up close.
Bottom trim clip removal up close.
IMG_20201227_141343.jpg (589.73 KiB) Viewed 377 times
It's necessary to remove both attachment loops and the second row seat belt clip (not the one for the third row). The accessories socket remains in place, the wiring harnass is unclipped from the back of the panel.

Inside trim removed.
Inside trim removed.
IMG_20201227_141744.jpg (710.93 KiB) Viewed 377 times
Fortunately, in typical Nissan forward thinking they marked the spot and what we want is under the giant X.

Location and removal of resistor board.
Location and removal of resistor board.
IMG_20201227_143957.jpg (660.59 KiB) Viewed 377 times
These four wires plug into the resistor board which is held in place with the two visible screws.


Repairing the problem
Dirty resistor board.
Dirty resistor board.
IMG_20201227_144355.jpg (852.66 KiB) Viewed 377 times
The damage to the board is easy to spot, even through all the dirt and what looks like corrosion.

Visible damage.
Visible damage.
IMG_20201227_150247.jpg (603.31 KiB) Viewed 377 times
Visible damage.
Visible damage.
IMG_20201227_150328.jpg (1.2 MiB) Viewed 377 times
I expected the damage to be the fused link, but what looks like corrosion and heat damage caused the track from the input to disintegrate.

Damage bridged.
Damage bridged.
IMG_20201227_150735.jpg (495.15 KiB) Viewed 377 times
A short section of the track was cleaned on either side of the damaged portion and a few mm on either side bridged with a piece of wire.

Testing repair.
Testing repair.
IMG_20201227_150720.jpg (705.49 KiB) Viewed 377 times
Testing continuity.


Most of the time spent on this repair was removing and installing the trim to get to this board.
2004 Nissan Patrol 4.8
2006 Nissan Hardbody 2.4 D/C 4x4

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JohnBoyZA
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Re: Rear AC fan speed control repair

Post by JohnBoyZA »

Great post Paul, thank you for sharing!
Nissan Patrol, GRX, 4.8 (GU Y61)
Flickr: http://www.flickr.com/photos/jhemurray/sets/

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