84 to 86 Duke retrofit

[dguy]

Next victim is the harness which runs along the driver's side floor.

In the 84-85 cars, this covers the rear window defrost, door ajar switch, seat belt in-use switch, and e-brake warning switch.

For the 86+ cars it's virtually identical, except that the door ajar switch is replaced by a 3rd brake light.   

The original routing for this harness places it along the door sill for a bit, then it goes for a big wide loop under the driver's seat before returning to the firewall/door area and heading up to the window.  Why?  Beats me.   

There's plenty of room under the e-brake handle to run some wires without danger of pinching, so I cut about 8 inches out of the harness before installing it, and re-routed the sucker.  Much tidyier now. 

[dguy]

As you can see, the 84's weren't set up with the mounting holes for the 3rd brake light fixture.   

[dguy]

Though I can't prove it (the donor car is long gone), I swear that the angle between the rear glass and the roof is greater in the 84 than it was in the 86.     No matter, I can deal with that.

First, trim away a bit of an outcropping in the center of the fixture.

[dguy]

Carefully center the fixture, mark, and drill some holes.  I used a pair of self-tapping bolts, and some washers to shim the fixture so that when secured in place, the lens is flush against the rear window.  The shims still need some tweaking, but you get the idea.

I have a total of about 8 hours in to this so far.

[fiero308]

wow
you work fast, especially the part about keeping your hands clean for the pix!  How do you do it?
And another stunning observation on my part:
you didn't have any turkey sunday, did you?  Decided to spare a gobbler?  Or simply waiting for the proper day?
Great writeup Don; you might inspire someone to tackle a job that they otherwise might not; and the white car looks to be in superb shape!  Is it freshly painted (more or less?)
good thread; esp. the 'incidentals' as you get to them.
gp

[aaron88]

Nice work!

[dguy]

wow
you work fast, especially the part about keeping your hands clean for the pix!  How do you do it?

Well they weren't all that clean; washout from the camera flash gives the photos a bit of an illusion that way.     I did wash my hands before taking a number of the photos though.  After unwrapping much of the original electrical tape on some of the looms, I had fingers of a stickiness which only a kleptomaniac could appreciate.   

And another stunning observation on my part:
you didn't have any turkey sunday, did you?  Decided to spare a gobbler?  Or simply waiting for the proper day?

But of course!  Turkey, a couple of friends (though we didn't eat them), a bottle of wine, and a nice tawny port.  I finished playing in the garage just in time to enjoy all of them.

Great writeup Don; you might inspire someone to tackle a job that they otherwise might not; and the white car looks to be in superb shape!  Is it freshly painted (more or less?)
good thread; esp. the 'incidentals' as you get to them.

Thanks for the feedback!  (and from you too Aaron)

I got the bug to document the progress when mr.tourismo mentioned that he was considering a similar project, plus from time-to-time I see people asking about it on PFF.  So what the heck...  I'm having fun doing the work, pulling out the camera forces me to take a break once in a while, and if the info may help someone else down the line.  Not to mention that it'll be a handy reference source if I ever have a "why did I do that" moment.   

The paint on Sacha's car pre-dates Chris's ownership I believe, and is not the original.  It also looks like a Maaco job when you get up close.  The nice thing about white, is that it's good at hiding flaws.   

[dguy]

On with the show!

Given that the shifter has to be changed anyway, I decided to remove it before diving in to the wonder of the main wiring harness.  The fewer things to get in the way, the better.

[dguy]

The speaker seats have a sub-harness of their own, which runs the length of the center console.  In the second photo below, it can be seen running along under the brake booster vacuum line.

If you have an aftermarket stereo wich connectors which have been spliced in to the car's wiring, you may find it easiest to cut the connections for the front speakers, leaving the rear (seat) speaker connections intact.  Then simply reconnect the wiring for the front speakers after you have installed the 86 harness.

If you have an aftermarket stero which uses adapter plugs to connecto to the car's wiring, or the factory stereo, it may be easiest to release the terminals for the rear speakers from the connector's shell, then switch them with those for the sail panel speakers after you have installed the 86 harness.  Most terminals can be freed from their shells with careful use of a jewler's screwdriver or other small pointed tool.

[dguy]

If you want/need to make any changes to the main wiring harness, now is the time to do it.  It's much easier on your flexible (and inflexible) body parts to attack the harness with a soldering iron while it's spread out on a work bench than it is when it's in the car, trust me.

I took the time to

• set up any other needed connections for the aftermarket stereo;
• bundle up the now unneeded wiring for the 86 sail panel speakers, rather than to un-tape the harness and extract them;
• move the connectors for the lighter socket from the 84 harness to the 86 (previous owner had cut them off for some reason);
• clip the wire which activates the blue dingy thingy's parking brake alarm.

Now...  from here on in, at least with respect to exchanging the main wiring harnesses, it's pretty much a "plug and play" operation which becomes self-evident when you start working at it.  Rather than post a complete play-by-play, I'm simply going to point out any "gotchas" that I ran in to, or things which I feel may not be obvious to everyone.  This is by no means a bible!

The basic idea is to disconnect everything up behind the steering column & instrument panel, disconnect the end of the harness in the engine compartment (C500), and untangle the whole mess from the chassis.  Easy, right?     Work at it slowly, don't force anything.  It's all possible.  If it looks like it isn't and it's frustrating the heck out of you, take a break.  Unless the interior of your car is in unusually poor condition, you shouldn't ever need to go get a bigger hammer.

To make things easier, remove the lower air deflector from the heater box.  It's held in by one 7mm bolt from the driver's side, and will come free if you pull it sharply toward the steering column.

[dguy]

There are three harness grounds which are connected to the chassis by 7mm self-tapping bolts.

One below and to the left of the ECM if you sit facing it, one on the driver's side of the upright which acts as a "leg" for the steering column/instrument panel support, and one up and to the right of the steering column (shown below).

This particular ground is not part of the main wiring harness; rather it is for the optional rear window defroster harness.  But... many times it gets pinched and/or cut when people raise/lower the steering column.  By disconnecting it now it becomes somewhat easier to move the defrost harness around, not to mention that if the ground has been cut, it's a good time to repair it.

[dguy]

If anyone has ever wondered what the under-dash wiper delay module for the 84's looks like, and where it's located, this is it.  Apparently there's another harness ground in there which I forgot to mention in my previous post.   

[dguy]

The "convenience center" will fit through the space between the steering column support and the front bulkhead if you unplug all of its components.  It also has sufficiently long wire to make a nice rat's nest around the brake pedal.

[dguy]

Lower the steering column, so that you can both disconnect the harness from the ignition switch, and work the harness around it after everything has been disconnected.

[dguy]

If you have a rear window defroster, you should find a pink and a brown wire plugged in to the back of the fuse panel as shown here.  Try to remember where they go, but don't get upset if you forget--both connectors are keyed.