I take it you've never seen a 'Lucas Meltdown'? Curent keeps going until everything burns....some circuits are unfused. Keeps going like the Eveready Bunny.....

It's only a silly bunny, he says....but it's evil, with fangs that go Fffphht, fffpht.....bring us the Holy Handgrenade....

........you probably connected a live wire to a ground terminal......happens all the time......I have yet to see a body shop that hooks up all the wiring correctly and I have been in the car repair business for twenty some years.....
REMEMBER: GROUND IS ALLWAYS A BROWN COLLERED WIRE, SOMETIMES WITH WHITE STRIPES FOR TEMPORARY GROUND ON ALL OLDER GERMAN CARS.

CHEERS !
WITT !

Right, Witt...
As for you, JB, all I can say is (besides the fact that you have a very interesting way of describing DC circuitry) the man had no problem 'til turning the key; most of the wires are not 'live' that he was messing with, ignition being off. The problem would have arisen had the battery been at first disconnected or not, because he would have reconnected 'the fargin' thing' to try the key.....good night, bunny....*(&*

Sorry about your pain. My suggestion in the dead horse beating dept to you and every one who says it won't happen to me is to fuse your instrument wires from the ignition switch. It is well documented here.

911 Dash Electrical Fire Prevention
by Steve Grosekemper

One of the most terrifying experiences a Porsche owner may ever be faced with is an electrical fire while driving. A short in the dash illumination circuit usually causes the situation. The problem with this circuit is that it is unfused. When part of the circuit shorts to ground (usually caused by chafed wiring, bad bulb holders, or other unexplained circumstances), the current load greatly exceeds the capacity of the wire, causing heat, fire and of course highly elevated repair bills. The overheated wire lives inside a large wiring harness, which takes only minutes to be completely destroyed.

Fortunately, this disaster is easily averted. An inline fuse holder can be installed at pin # 58L of the headlight switch. Then if a short does occur, the fuse (3 amp) blows before any damage is done.

Installation instructions:

1. Disconnect the battery.
2. Remove the headlight switch.
3. Disconnect the black and violet (#58L) wire from the switch.
4. Install an inline fuse holder between pin 58L and the black and violet wire.
NOTE: Install connectors at each end of the fuse holder (1 male, 1 female, spade type).
5. Insulate wire end of fuse holder with 3/8" heat shrink tubing.
6. Reinstall headlight switch and reconnect battery.
7. Turn on the headlights and remove the 3-amp fuse from the holder. Did the dash lights go out?

Congratulations! Your update is now complete (after you reinstall the fuse, of course).

Good Luck!

Thanks....especially like the, "...after you reinstall the fuse, of course..." :) Good one!
Seems a little more detailed instl instructions between 4-6 above would help for those who have not messed with heat shrink tubing, male/female connectors, et al....
Oh, and shouldn't it be, "each side of fuse holder...", etc..... diagrams maybe, though simple, would be wonderful; probably out there already? Thanks for the post, Rick....good stuff IMHO. Still gotta get those wires right or risk blowing a bazzillion nickels' worth of fuzzes!

OK...that Lucas smoke thing is funnier than sheet.

Ah..try figuring out this Jaguar schematic :D
http://forums.pelicanparts.com/uploa...1322804931.jpg

WELCOME to the fried dash wiring club.

Here's what probably happened. Over the years, the wires chafe behind the gauges. This wears the insulation through. You re-orient them and the bare portion touches against the body sheet metal, and it's party time.

Can I make a suggestion: replace the factory wires with EXACT replacements. Make your repairs indistinguishable from the original. This preserves value in two ways:

1) Even if you disclose that you had an electrical fire when you go to sell the car, when a guy like me looks behind the dash and sees that you did it right, this inspires confidence. If somebody sees non-standard wires, Radio Shack faston connectors, or what looks like improvised connections, they tend to RUN; and

2) Diagnosis of this problem over the Internet is only possible if you use the factory colors and wire sizes. I chuckle at all the guys who are hell-bent on "upgrading" things like their fuse box-- there will come a day in which they have an electrical problem, and diagnosis in a reliable way will be impossible because they will always be wondering whether the "upgrade" was correct or not.

So you need three things:

1) The FACTORY wire diagram. This is in the back of the workshop manual. If you have to buy the manual to get it, make the investment.

2) An F-type crimper. I recommend the Knipex 97 21 215B http://www.early911sregistry.org/for...1&d=1311817791

3. Factory wire, original brass ends and rubber covers for the wire. Available either at
YnZs Yesterdays Parts | Auto Wiring Harness | (909)798-1498 or
Rhode Island Wiring Service Inc.

Make sure you measure the wire diameters with a digital caliper to be sure you are replacing with the exact size (or the closest AWG equivalent you can find)

And while you are in there, put a fuse on the gauge illumination.

Good luck! A couple of weekends and you should be through it.

thank you guys, i am going to start today,

i had the battery disconnected, and in this instance, would not have made a difference, it happened as soon as i turned the key...

i have removed a ton of extra wiring harnesses from the car, and saved them in a box, i have most of the correct color wires that i can pull from there...

i just bought new connections and some shrink....need to brush up on my sodering skills

Good advice always, but I believe the OP's problem was shorting a signal wire for the oil temp or pressure gauge to ground -- the article describes fusing the lighting circuit only so (as I understand it) it wouldn't have helped.

Any tutorials on fusing gauge wiring other than illumination?

here is a great example of why you need to check the entire wire (and harness). this was the line that fed the ashtray light. it had power for about 4 seconds before the smoke filled up the car and i turned the key off.

http://i15.photobucket.com/albums/a3...e/100_5372.jpg

Soldering a connection is great and is indeed the best way to connect two copper wires together, but it can be impractical and if you're in a situation where the harness is under a dashboard or simply in very tight quarters, don't hesitate to use a but connector. I spent a lifetime doing installations and a crimp done by a professional is quick and 95% as effective as soldering at in a fraction of the time.

A layman doing electrical wiring stands a better chance at making a good crimp than making a good soldering connection.

The Factory crimped. They used a much more expensive crimper than the one I showed you, but with some practice, you can make identical crimps.

What do you mean you removed "a ton of extra wiring harnesses?"

Did I miss what car you have? I'm working on the 3.2 wiring diagram at this time, but not sure how much I can help. You may have to trace wires by color to see what ones are burned and pull those fuses... I don't know what to tell you at this point, others will know an approach. There are a number of wires that are not fused on the 911 depending on what model you have.

I skimmed the responses, and didn't see this in large enough print:
INSTALL A FUSE.
The reason you melted your wires was one or more shorted, probably a chaffed wire. If you kept track of what was what, I doubt YOU caused the issue. (So don't beat yourself up) Probably an old worn, chaffed wire.
But, all circuits on the car are NOT fused. (I'm sure this is in Jack Olsens "dumbass things the genius Porsche engineers did" thread form 6 or so years ago...well, that's not the exact title, LOL)
So, get a wiring diagram, and look it over. Add inline fuses near the original fusebox for unprotected circuits. This wouldn't have resulted in the mess you have if that had been done.

(I'm sure this procedure has been detailed here, perhaps a thread will turn up better instructions.

Check post #21....some circuits are unfused....Porsche engineers aren't perfect.

As to my comment on the battery.....I always assume I would screw up. So 'I' would have in this issue energized one gauge at a time and had a fire watch on the battery connection....call me stupid but knowledeable due to stupidity by repetition.

I learned crap can happen from English cars. I owned not one but three Austin Healy's.

If'n I kept those pieces of crap I would be 300K in the black.

Is there a list of unfused circuits to look at some where? I've already got the dash lights in my sights.

i removed all AC harness, heat harness, mirror harness, things that were not being used, that was months ago, and totally unrelated to this, the car was fine for the last year.

this was deff a mix up in wires, and i am almost positive i know which ones,...it was the red and black wire to the back of the oil pressure gauge that started it, and one of the brown jumper wires

i replace the brown jumpers all the way to the ground and through the loom...

the red wire is traced back all the way to the plug under the dash, its all apart, my goal is to replace today

i can soder really good, atleast i think so, and the two wires i was able to reach came out perfect.

picture of my repair, i think they came out really good

http://forums.pelicanparts.com/uploa...1323738252.jpg