This file started out as my outline for doing the dash conversion on my 82 Coupe. I was installing a nice dash with no cracks from an 86 4kq. At the same time, I modified the center vents to deliver heated air and fixed a bunch of little things. This file is presented in approximate chronological order of the project, but is internally cross linked so you may jump around from section to section as you need. I recommend reading the entire file first if you are planning on undertaking this project - some sections relate very closely to others, you may want to organise the work differently than I did, and this is not an endeavor to undertake lightly or with insufficient planning.
Feedback? If you have any questions, insights, or improvements, catch me on the Quattro list at Audifans.com!
The most important part of a project of this scope is to test, test, test! You should test any functioning apparatus before each stage of reassembly, to avoid tedious disassembly and troubleshooting! The car will run without the instrument panel in place. At any point, if in doubt, check all functioning systems!
Work neatly, do not allow stray wires to short out on anything, this could cause a problem with testing at partial completion stages. It's a good idea not to cut wires until you are ready to splice them. If you carefully bundle disconnected wiring and fasten it out of the way it will be easier to check for strays before powered testing sessions. If you are not certain you can re-identify a wire or piece of hardware, label it carefully - it would even make sense to keep an index of your labels! An instant camera can be very helpful, it lets you document how things looked before you took them apart for later reference.
Work with the battery ground wire disconnected, for safety and to ensure you don't accidentally toast some vital part of your car's anatomy.
For this project you will need these parts from your donor vehicle(s):
Be certain battery ground is disconnected!
Remove the following:
Driver's side - first, there may still be a cardboard cover extending this to the firewall. It usually has one screw, at the front left corner and a clip at the heater outlet, over on the right side. Then, there are three screws going up into the dashboard and maybe one into the side of the car. The early version has a couple more screws than the later one. The later one only has the three screws into the dashboard. When the screws are out, very carefully lower the panel, pulling it away from the center console at the same time. There are three plastic pins that go into the center, and they are very prone to breakage.
The passenger side is much the same, except for being completely different. There are screws inside the glovebox into the center console. You will also find that the ECU is screwed to the outer edge of the glovebox. Be careful with this unit, leave it connected, in the car, and out of harms way, since you will be starting and running the car with the glovebox out of the car. One fo the two screws holding the latch in place goes into sheet metal, the other uses a captive nut and is left in place. The glove box light wires or socket must be separated to allow removal.
On both sides, in addition to the invisible, fragile plastic pins going into the center console (consider yourself accomplished if you are able to maintain two out of three of these in working order after three remove/installs of these pieces!), there are usually some sort of fixture devices at the top rear corners, inside the cubby and inside the glove box. These seem to consist of a metal hole in a bracket on the car, perhaps with a rubber grommet in it, and a plastic plug thing that goes through the hole in theback of the underdash piece and pushes into the grommet. These help stop these bits from sagging by supporting them at the opposite end from the center console.
New and old are a bit different. The old style is held on by two screws up into the front plate and two down through the main cover, I think (it's been a while as I write this!). The new style has four screws, all pointing up, two at the bottom and two at the top, through the front plate. This removes the front of the cover, freeing up the switch housing and main cover. Pull the switch housing gently towards you a bit, then the main cover just pops off, if you spread the sides a bit to clear the cluster. Be careful not to break the little side vents. Now gently pull the sockets off the switches and remove the switch housing and switches still together. The headlight switch in particular is very difficult to remove without breaking the housing. I searched far and wide to find a housing that wasn't broken already. Now cut off the sockets and as much wire as you can get from the donor car.
First reach around the back and unscrew the speedo cable locking ring. There are two main wire connectors, which are keyed but I think they are the same size. Don't mix them up. There are also one or two minor wires attached to the back, it's probably a good idea to keep these organised. All I know is the next time my OXS counter went postal, it was my ejector seat light that came on, not the OXS light... The cluster is held down by a pair of screws, it may be easier to remove them before undoing the wires and speedo cable.
This is held in place and assembled by all kinds of wacky screws around the shifter and ashtray, and about four up into the dash, two just above the heater controls and one on each side into clips on the heater plenum (I think). The heater knobs must be pulled off and the panel removed, it's held on by "goo". I find the later style a bit easier to pull apart and reassemble, I think this is because of the soft plastic edge trim that kind of goes over everything last. As this comes out of your car, a lot of important bits are going to be dangling around. Try to keep track of what they are - anything you can't immediately recognise and identify should be marked and its location, connections, etc. should be noted very carefully.
First remove the three air vents by reaching behind the dash and compressing their plastic spring clips. They pull toward you out of the dashboard, and the air pipes just pull off the ducts behind them. There are five nuts holding the dashboard in place. One at each end in front of the firewall, one at each end inside under the air vents, and one behind the ducting to the center air vent. Then the dashboard just pulls up and backwards out of the car.
This entire job can be done with the steering wheel in place - but it is easy to remove and replace, and does make it easier to manouver. Of course if you are replacing the column stalk switches as well, it has to come off.
Now is a great time to do something about the speakers in your new dash.
Stock, the center vents in the 80-87 Coupes and 4000's only deliver fresh air even while using the heater, which some may like, but I don't. I want both my hands to be warmed in the winter! So I modified mine to provide the same air, heated or not, as the rest of the vents.
I recommend getting a spare set of ducts. This is pretty easy to do if you are obtaining dashboard parts for the upgrade! This allows more confidence, in that you can put things back together stock if you screw up. This also gives you practice removing them!
You will see the two separate bits of ductwork, one to the side vents, one to the center. The side ones come from the heater box, the center one is fed from the fresh air plenum (but after the A/C?). They almost touch in two places, one on each side of the center. This is the key. You are going to block the fresh air from the plenum and cut holes in the two ducts and join them.
Mark the ducts as best you can (just the top one, center, is enough) so you can align them off the car to cut and drill. Again it helps to have a set off the car to monkey with and get a feel for how they go together.
Remove the ducts. Place them on your bench as they lie in the car
Cut off the excess from the center duct (everywhere it goes forward past the side duct) at an angle, leaving intact the whole area of contact and an extra cm or two on the bottom, and less on the top. Drill, carefully, a pilot hole in the very center of each area they overlap, this will align the larger holes you drill. Then, drill the larger hole through both ducts. I used a 1-1/2" hole saw, it might be possible to go bigger than that. Deburr all the cut edges.
To join them I used black RTV, and a couple of pop rivets (again drill pilot holes for them). Then I blocked the cut open inlets to the center piece with some scrap plastic, again using RTV to attach.
Set the assembly aside to dry overnight. You can do other things you've planned in the meantime, like rewire your switches or drink lots of beer.
Block the fresh air plenum outlets with whatever you've got handy (duct tape?) The old center pipes make a good template to take to hardware stores looking for the ideal bits to make plugs.
Install. The center vent will be a hair lower than it was but it will still mate with the outlet section.
Note: Using the 1-1/2" hole, I find a little less air goes to the center than the sides. There is only room for that size on one side, the other could have been larger. Still I am very happy with the results! I apologise for not photographing the assembly while it was out for others' reference.
After installing the main dashboard...
The instrument cluster switches and sockets are all different and you will have to splice the switch wires - solder and shrink wrap them to do this right. I analysed the old and new switches and to my relief most of the color codes are the same. The emergency (four way) flasher is a bit weird, but only a couple of wires really require thought. The internal switch lights are handled a little differently between the dashboard types but if you can splice 30 wires you can figure this part out yourself I'm sure! Email me if you need help. The only way to avoid this chore is to swap the wiring harness back to the fusebox (and the fuse box as well unless your car is an '84) - which would be the way to go, of course, with a stripped down restoral project.
The following is a breakdown of what I figured the switch wiring to consist of:
Install new dashboard with speakers and 36" wires.
Now is the time to splice the switch wiring (see previous section)... and test each switch as you go!
Install instrument cluster and make sure it works properly - a little dirt or whatever in the main wire harnesses can screw up various functions. You can actually drive the car in this condition - although it can be a bit weird, none of the internal visual cues are where they belong. So be careful when you do this. Make sure no wires or hoses are going to interfere with the steering or pedals!
At this time, you may want to clean up any aftermarket stereo wiring, do any extra wiring for aux. switches (fogs etc.), since all your gear is out and you are getting good at this. I did the following...
Installed a used pair of defrost switches operate my foglights and extra low beam (city lights) function. I mounted these upside down on the left side to keep all the lighting controls together.
Rewired the upshift indicator to be my fog light indicator - one side is always 12v, so your switch must ground the other side of the light. There is a brown/green wire to the upshift relay which is the one you ground to activate the light.
Rewired the radar detector - I have a remote Whistler that is about 15 years old, I set it up to trigger a reed relay so it can deliver some current, and run two blue light bulbs installed in the inner sides of the instrument cluster, and a very loud buzzer, which I mounted to the sheet metal forward of the instrument cluster, hidden under the cover of course.
Rewired the cigarette lighter ground - this really helps - it no longer affects the console gauges and works faster. I have an Audi multi pin ground thing mounted on one of my shifter housing mounting bolts for this and the stereo grounds.
If you want to install entry light(s) in the footwell(s) now is the time to figure out how. When I do this I will try to get a delay timing relay so they stay on for a few moments after the door is shut.
I tried to use Audi style wiring in all these applications, you don't have to, of course, but I think it helps to keep the same "logic" and conventions throughout the vehicle if possible. I also add extra circuits to my diagram in my Bentley or if they are very independent of the rest of the car, add an extra sheet to the manual (mine is loose leaf - very loose...).
Put the new cowl over the cluster, and install the switch panel and switches. (Need I remind you to test everything AGAIN before sealing it up?)
Install the center console... carefully tucking all the junk that belongs under it!
Adjust CC vacuum switches properly (PITA) - hey, you're in there, why not?
Make sure any wiring under the dash you worked on is neatly wrapped and tied down - and test everything again just in case!
Install the left side underdash panel and cardboard cover. I worried about fuse access, since the cars up to 1983 have their fuses under the dash, accessed by a door in the underdash panel. The later style dashboard cars all have the underhood fusebox and so have no provision for this. I've discovered since doing this job that the fuses and relays can still be accessed quite easily.
Go over to the right side...
There are a few more things about the later model cars' interiors that are nicer, and worth swapping if you get the chance. While neither has to be done at the same time as the dashboard project, you may want to acquire the parts while you have access to the donor vehicle. One is the signal/wiper stalk switch assembly. It is nice looking and allows a cruise control "coast" function. It will require the switch sockets and a bit of wire to use properly. I'm sure at this point you can figure out how to do something like this (hint: the coast function interupts the power to the control unit in the same way as the clutch and brake switches). The other item is the handbrake lever, which is bolted to the floorpan and has a rod going to the equaliser at the cable underneath the car. Careful, some cars use one cable and others use two separate ones, they use different equalisers. I broke the connecting rod undoing the nut on the end of my donor, but a new rod and rivet were cheap at my Audi dealer. There is also the interior light to grab if you are dealing with a coupe donor and recipient.