Dash removal.

[flamebero]

This probably been covered a million times (but I couldn't find any), or something obviuos I'm missing. How do I remove the dash? Or is there a better way to get to wires for tracing purposes? I'd also like to figure out how to remove the radio. Thanks!

[sunsprit]

On a '78, you need to remove the center console panels to "trace" the wiring, as all of the wiring harness is under the dash area. It mainly loops over the steering column from the fusebox area, then across under the radio to the right front emissions controls under the glovebox. A large bundle of harness branches off from the center area down to the switches/warning lights contained in the console, and another bundle branches up to the 3 gauges and the 4 warning lights above the radio.

The radio is typically held in with the two nuts behind the knobs, although a sharp installer may have added a third bracket behind the radio to better support it. Additional brackets would be readily visible with the center console removed.

The center console side panels come out with the removal of a few screws on each side to the center, a bracket between the panels below the radio, and a bracket across it at the end area. Not a lot of hardware holding it in, but it's fussy to remove and you'll still have to deal with moving the center panel to one side ... it's got the hand throttle and heater controls, along with the switches (fan, wiper, instrument lights) mounted to it. You may find it easier to maneuver this panel by removing the switches from the harness, but be careful to make your own wiring diagram so you can readily re-install the wires on all of the switch connections ... a couple of pictures with a digital camera may help, too.

I just got through doing a wiring repair job on a '78 Spider, which had a lot of the wiring harness damage due to the emission control relays/panel under the glovebox having melted down/shorted out. The power wire to this area melted the insulation on a lot of other wires in the wiring loom, causing the wiper and heater switches, along with the 4 warning lights by the dash gauges to be non-functional. With a couple of spools of wire (different colors), heat shrink tubing, and my trusty soldering iron and heat gun (to shrink the tubing) ... splicing in repair portions was easy with the center console side panels out, although tedious work. I just cut back the wires as needed when I separated the looms and rewired as needed. I prefer to solder in wires and use heat shrink tubing rather than using "crimp on" type connectors which are bulky and can fail over time (with high resistant connections).

Having the laminated full color wiring schematic for the '78 car greatly helped in tracing out the damaged wiring. It also made it easy to trace out the "dealer mod" for the power to the aux in tank fuel pump ... which was "scotchlocked" into the power supply wire for the OE main fuel pump. It's now soldered in, and gives much more reliable power to the secondary fuel pump.
Anytime I have questionable factory crimped connectors in these cars, I will solder them in .... replacing questionable connectors as needed ... helps eliminate electrical problems in gauges, charging, ignition, and other systems in the cars. Also, I use the pointed glass Buss fuses instead of the soft solder strip on European ceramic fuses ... much better connections and you don't have the high resistance of the soft solder element fretting into the fuse box spring strips.

[Inner Circle]

Tracing wires behind the dash is good fun, provided you're heavily into S&M (as you'll inflict and receive much pain) and have unusally long and thin arms (and, preferably, neck and head too). The wires suddenly dive into inconceivable little hollows, entangle with each other and generally have good fun avoiding any tracing attempts. So I had ENOUGH, pulled the dash, pulled the whole wiring, rewired the whole stuff and this time, bundled the wires together - because in the factory configuration of my '74 Spider, all the wires just went wherever the hell they felt like. It took forever (still there are a few kinks to work out in the system) but now at least I know which cable goes where. (I also installed relays for the lighting and the steering coloumn switch.) So even though my car is European and, as such, might be differ from yours significantly, feel free to ask if you have any questions about the wires... right now, I feel like I know them better than anyone, anyplace, anytime had ever known the little sneaky snakes. Maybe you can avoid pulling the dash. (But if you do, a couple digital pics will surely help. Even more pics would help even more :-) )
Here is my old wiring on the garage floor (dead and beaten after a vicious fight), focusing on the dash wiring, and a pic of the firewall from the inside, showing how the wiring branches off after entering from the engine compartment. (Also, note the rusty surfaces. It's been taken care of, but still, not a pretty sight.) Normally this piece of wiring is invinsible, as not only the dash covers it, but also there's the little plastic air duct that carries air to the left side vent from the scuttle. Hard to remove and harder to install again. And when in place, doing a great job of obstructing your view (and feel) of the wiring. Fusebox is connected to the wires on the bottom right corner.
So, good luck!

[flamebero]

Thanks for the great, and detailed advice. I should be able to get started on it this week. Hopefully I can fix my heater switch while I'm at it. Sounds like I should pick up some shrink tubing aswell. I'v usually just used electrical tape in the past. Were did you find your wiring diagram fo your 78? Thanks!

[ghnl]

If you do remove the dash (and removing the console is about 75% of the work) I suggest you take that opportunity to remove the heater unit to clean and lube the blower motor. It sits down in the bottom of the heater - any water that gets in there does the motor no good.

[Zunige]

For wiring diagrams see the Electrical forum sticky Available Wiring Diagrams, and contact BB member "papajam". (He actually draws these large colored wiring diagrams from scratch!)

Best regards,

[ga_mtn_spider]

It woud also be the perfect time to replace the cowl drain hoses and heater hoses.

[Ohiospider1975]

Do the dash attachments (fasteners, glue points) tend to break during removal of the dash, or is it safe to remove the dash and expect everything to function (fasteners, connections) during reassembly?