1986 Turbo GL to GLL conversion

1) Digital Dash

most people will be wanting to attempt this conversion to GLL to gain the digital gauges in place of the analog so i'll start with this conversion first and will list out the parts that I needed to gather before starting in on the conversion.
Yes I realize most people are trying to do the opposite but there are those out there like myself that enjoy the digital and thankfully I've been lucky that everything works even after 28 years!

Digital Dash

here is the list of all parts I required to ensure the digital dash would work once installed in my 86. Some parts were available new from Nissan and others I sourced through people here like MADMIKE or another great site for parts 300zxpartsforyou.com

1) the digital dash itself. as mentioned elsewhere the digital dash between 84-86 will interchange as will the 87-89. For my purposes I was looking for the 86 digital dash which has the windshield washer fluid low warning lamp.
2) digital dash power supply p/n 24821-01P11
3) digital dash power supply mounting nut p/n 08911-10637
4) digital dash power supply mounting screw grommet p/n 96706-P0105
5) digital dash power supply mounting screw p/n 01466-00022
6) dash lid cluster (this is the black piece of plastic that surround the digital dash) p/n 24811-01P10
7) digital speed sensor (for 84-86 this is the sensor that mounts in the engine bay infront of the battery )p/n 25911-19P00
8) digital speedometer cable from transmission to speed sensor ( the part number for this varies depending on manual or auto trans)
9) GL speedometer cable rubber grommet cover for firewall ( since you will be removing the GL speedometer cable there will be an empty hole in the firewall that you will want to plug still available from Nissan) p/n
06212-3000P
10) digital gauge fuel sensor (available new from Nissan courtesyparts.com p/n 25060-Z31008) avoid used ones wherever possible as they are prone to failure as documented on this site
11) center digital combo gauge (compass and acceleration gauge) separate parts are available for turbo or NA but they are interchangeable just like the digital dash itself
12) compass direction sensor (mounts in the roof part # varies depending on 2 seat or 2+2) 2 seat p/n 25914-03P00
13) compass direction sensor mounting screws ( 2 required) 08543-51090
14) compass amplifier (installed in rear hatch) p/n 25916-01P00
15) compass amplifier mounting nuts ( 2 required) 08911-10610
16) digital dash instrument harness for 1986 p/n 24013-19P20
17) Main body GLL harness for my purposes 1986 300zx Turbo 2 seeater automatic GLL p/n was 24010-19P62

GLL radio/GLL steering wheel and switch controls

1) GLL steering wheel with cruise and audio controls
2) GLL steering column cover
3) GLL steering column headlight/wiper switch assembly
4) GLL steering wheel switch receiver 25696-01P20
5) GLL steering wheel switch receiver mounting screws p/n 08510-61212 and 08510-61223
6) GLL steering wheel switch receiver DIN cable p/n 28378-01P01
7) GLL radio p/n 28115-19P00 or 28115-17P00
8) GLL radio amp p/n 28063-17P00
9) GLL radio to radio amp DIN cable p/n 28378-17P00
10) GLL radio amp mounting screws (2 required) p/n 08513-61212
11) GLL radio dash tweeters 28145-01P00 RH and 28146-01P00 LH
12) GLL radio dash tweeters mounting screws (4 required) p/n 08313-51212
13) GLL radio sub harness 24016-17P01 or 24016-17P00 or 24016-17P51
14) GLL radio amp metal floor panel (located under the carpet under the passenger side seat. Panel is required as it is what the GLL radio amp mounting screws screw in to)

Automatic Climate Control
1) auto climate control unit (any year auto climate control unit will work)
2) incar sensor roof
3) in car sensor roof mounting screw (2 required) p/n 01461-00061
4) in car sensor roof mounting bracket p/n 27709-01P00
5) in car sensor roof grille/cover (varies by interior color code)
6) GLL roof headliner (varies by interior color code)
7) in car sensor driver foot
8) in car sensor vent
9) in car sensor defrost vent
10) sun sensor p/n 27705-01P01
11) sun sensor vent/grille (varies by interior color code)
12) sun sensor sub harness p/n 27583-01P00
13) control unit sub harness p/n 27585-17P00
14) GLL clock (GLL has grey/green backlighting instead of GL orange)

15) Blower motor unit (GLL blower has the foot temp sensor mounted to the bottom as well as the digital amplifier)
16) Blower motor unit wiring harness p/n 27267-01P10
18) Heater core unit p/n 27115-01P02
19) heater water cock with temp sensor for engine bay p/n 92230-01P12.
20) heater core wiring harness p/n 27582-01P10
21) ambient temp sensor and bracket (bolts to front bumper) p/n
22) a/c unit assembly
23) a/c unit assembly wiring harness p/n 27580-17P01

misc. interior

leather seats
GLL seat belts with retention mechanism (GLL seat belts have electrical connectors for the retention assist)
GLL leather door panels
grey/green bulbs for instrument switch backlighting (replaces GL orange backlighting 2 required) p/n B7677-01P02
grey/green bulb for auto trans shift indicator assembly (replaces GL orange backlighting 1 required)

Now for the part everybody has been waiting for the conversion itself from GL to GLL and I'll provide as much of a how-to step by step guide as possible.

A few notes before getting started

If you are going to change from manual to automatic climate control now would be a good time to drain the coolant.
I can't stress enough how important labelling the screws as you remove them is, so that they all go back in the right place.
and last and maybe most important. During the conversion you will be removing the metal dash crossmember. It is very important that the car not be driven or jacked up while this metal crossmember is removed.

removing everything GL

I won't spend too much time discussing removal of individual components as it's pretty well documented already in other posts.

You will need to remove absolutely everything in the interior except for the door panels at this point.

Remove the sunvisors and rear view mirror.
Remove the headliner
Remove all the rear hatch trim
remove the rear hatch carpet
remove the seats
remove the center console
remove the carpet
remove the hidden luggage compartment for 2 seater models
remove the interior panels by the seatbelts

When complete the entire interior should be removed so that the entire length of main body wiring harness is accessible from the rear hatch up to the firewall as it will need to be removed.

Dash removal

remove the radio/climate control assembly
remove the glove box
remove the steering wheel
remove the steering wheel column cover
remove the speedometer cable from the back of the analog dash unit.
remove the instrument switches
remove the dash plastic trim
remove the analog dash
remove the dash assembly
remove the metal dash crossmember.

-removal of the dash and the metal dash crossmember are up to this point probably the most diffcult. A lot of cursing will probably occur. As noted elsewhere the dash vents will need to be removed in order to unbolt the dash for removal. Prying these clips isn't the easiest thing to do with the windshield in the way.
The metal dash crossmember is bolted in multiple locations on both the driver and passenger side. As well the two bolts securing the steering columb to the metal dash crossmember will need to be removed.
IMG_1230.jpg
this picture shows the dash removed with the metal dash crossmember installed
With the dash and dash crossmember as well as the entire interior removed the main body harness will now be accessible.

Starting at the rear hatch disconnect all the wiring connectors for the main body harness you will be able to pull the main body harness up to the front of the car disconnecting sensors and connectors as you go.
Now the hard part.

You will notice the main body harness on the drivers side firewall cannot be removed quite so easily.
The main body harness is installed behind the steering column metal bracket attached to the firewall and the brake pedal bracket.
IMG_1232.jpg
the red metal is attached to the firewall. The unpainted metal in the picture is the brake pedal/steering column bracket
you will need to seperate the brake pedal bracket from the steering column firewall bracket in order to slide the main body harness between the two and away from the firewall

IMG_1234.jpgThe brake pedal/steering column bracket is held in place by 4 nuts attached at the firewall by the drivers foot.
Remove the 4 nuts as well as the cotter pin securing the brake pedal assembly to the brake booster.

With the brake pedal bracket now free from the firewall you will be able to lower the entire brake pedal and steering column assembly away from the firewall bracket.
This will create enugh room to slide the main body wiring harness between the two pieces.

A note of caution here. While it is necessary to lower these pieces by an inch or two for removal of the main body harness you will want to minimize the amount that you are moving the steering column assembly. any jarring of the steering column assembly can damage the power steering rack. You may want to disconnect the steering column from the power steering rack to prevent damage to the rack or the seals.

brake.jpg
Once unbolted the brake pedal bracket will be lowered by a few inches to allow the main body harness to pull towards you fitting between the brake pedal bracket and firewall bracket.

After this remove the rest of the zap straps holding the main body harness to the firewall and disconnect the remaining electrical connectors.

The main body harness has wiring running into the engine bay on both the driver and passenger side.
Disconnect the main body harness connectors in the engine bay and tie a string to one of the connectors on the driver side and a string to one on the passenger side.

You will need these pieces of string in order to pull the GLL main body harness from inside the car back into the engine bay