Wiring warning

[Guest]

Some out there may be aware of the techinical note on Pelican refering to the instrument lighting circuit warning.
For those not aware; Porsche have omitted to protect the circuit that supplies power to the instrument lighting. It is not un-common for 3.2' s to burst into flames from this circuit. Ok; that sounds alittle un-realistic, eh? Well check this out....
Having read the Pelican warning, I purchased an in-line fuse holder ( a whole £2.00), complete with a 5 amp fuse, with a male and female 1/4" spade connectors on each end. This I fitted to the terminal on the rear of the light switch (easy to remove- disconnect battery fisrt). The terminal you want (there are many) has a blue/black wire on it, which is " piggy-backed" with a double (another blue/black). Disconnect the single blue black, connet fuse, reconnect single to other side of fuse. Remove fuse from new holder. Connect battery. Turn lights on. Headlights on but no instrument lights? Lights off and fit fuse. Lights back on; instrument lights on? Thats it!
But guess what?[8|]
Did the above and the new fuse blew?
Replaced it with another. Some time later (weeks), I had reason to remove the speedo. Poking around inside the dash I found 3 burnt wires, 2 of which were melted onto the top of a relay! It was obvious that this damaged had occured a long time ago, but what scared me was the fact that these were still " live" . And guess which circuit this was? Yeah you guessed it; the instrument circuit. Explains why the fuse blew when I fitted the new fuse holder.
I now have to make two circuits redundant (1/instrument and 2/clock/radio/interior) because I cannot tell how far the damage has gone. Clock circuit was also burnt. So now I have started to install a new circuit from fuse 4 on fuse box (section 1), through to the clock, and then junction (chocolate block) off to radio, and interior lights.
So take my advise, spend the £2.00 and fit that fuse![]

 

[Guest]

Excellent tip. Any photos just to make it easier DIY?

 

[Guest]

[] Just to add further to my entry above, the original warning was on the Porsche Club America site:
http://www.pca.org/sfl/911dash.htm
When I get a loan of a digital camera, I' ll post a few photos; but I' ve included a photo of a in-line fuse. Buy the type that comes with 1/4" connectors (Male & Female) on each end.[&:]

 

[colin smith]

Hi
My radio/clock doesn' t work and when I put a new fuse in it blows. It appears the last owner had to use the alarm bypassed at some stage and the problem comes from that. I had a look under the dash and quickly decided to many wires( I rthink looking though the paperwork the car has had 4 alarms over the years!!!). When it goes in for it' s new alarm this week I' m ging to use them to tidy it up.

Lets just hope they can, I don' t want a dash on fire!!!!

Colin

 

[Guest]

[] How about this weather?
Colin,
The clock shares the same circuit as interior lights (including glove-box), and radio. The radio actually has 2 circuits, one from the ignition key and the other from clock circuit. This radio circuit (clock) keeps memory alive in radio. As with alot of Porsche wiring, circuits have remained un-changed/upgraded since earlier models; but loads have increased.
Its very easy to run another wire (8 amp) from fuse 4 (section 1) to any other accessory. Check with your alarm people on what will be the max amp draw the alarm will use in full swing.
If the alarm uses 4 or 5 amps in siren mode, then use a different fuse terminal which has a higher rating, rather than the clock fuse which is light (5 or 8 amps I think); of course the temptation here is to replace the clock fuse with a higher rating fuse, but this will only increase the possiblity of damaged wiring to lesser appliances.[>:] Hope that makes sense?
Another trick I have learnt; find all the earth points and clean them; Bentley manual shows them in position. Also, pull out all your fuses (one at a time) and clean the contacts.
austa la vista- baby................![&:]