1983 SC Engine Bay light no lite...

[911 tweaks]

I looked in the archives & cannot find info on this one...does anyone know where the wires go from the lite on the underside of an 83' SC engine lid...?? I have no power on the 2 terminals no matter what position the key is in or if the parking or headlights are on & I cannot find the light in the Bentley or factory book...tried a different bulb too... what gives here...??...
Anyway, where does it get power from...?? All fuses in engine bay & front hood are good...stumped on this one...
Thx to whom ever can shed some "light" on this one..ha ha ha...sorry for the poor attempt at humor...
Bob

[Peter Zimmermann]

The engine compartment light fuse should be the number 4 fuse, counting toward the back of the car from the battery. That fuse also powers the front & rear left side parking lights (do they work?).

The lamp harness disappears behind the fuel filter, and I can't remember where it goes but it must join the main harness in the engine compartment. Have you looked for a corroded, disconnected, wire at the fuse box in the trunk?

[911 tweaks]

Thx Pete for your thoughts...now I have an idea on where to start...

Yup all of the other lites on the car work...was this an after thought by Porsche to add this lite as I could not find any info on it for the life of me on any elec dwgs or bentley...

I'll report back what I find...

Thx again...Bob

[fred cook]

The parking lights have to on and the rotating cover open for the engine light to burn. You probably know this, but never hurts to mention the obvious! Have you checked to see if the bulb was bad? Good luck!

[911 tweaks]

Pete Z...you win the prize...yup the 4th fuse back was blown & I thought it was ok...So I install a new fuse, turn on the parking lites and I hear a snap = fuse I just replaced blew...
Then, I removed the good bulb in the engine bay lite...installed another fuse...turned on the parking lites & snap again...
So............elect is my bug a boo...to avoid taking all of the lites apart, is their a more methodical approach to diagnose where the issue is...?? I would guess that I have a dead short somewhere = power is getting to grounnd somewhere in this curcuit, right...??

Thx Fred...got those bases covered... :-)

While I await your reply, I will start to disassemble the lites looking for any clues to a short ` grounding somewhere...

Thx, Bob

[Bob Kontak]

Check to make sure the light is not wired backwards. I am not sure but I think it can send juice directly to ground when you lift the little lid and can cook the fuse. Saying this as the passenger compartment light can do this if wired wrong. It may have a different ground setup though. Worth a try.

Here is the full page. See the tech info center for a full set of 82 diagrams. http://www.pelicanparts.com/911/911_Parts/Electrical/911_electrical_82SC_Part3-1.jpg

[Bob Kontak]

Terminal T1a is near the regulator panel - driver's side inner fender area . T6b is "Engine Compartment Right" - this is a six pole connector and you are looking for terminal 4.

[911 tweaks]

BK...I was hoping you were onto something = I closed the engine bay lid ie rotated its cover closed which should cancel it out of the circuit, no...?? and installed a 8.5 fuse as I am now out of 5 ampers and snap it cooked again...
I must have a dead short somewhere... now comes the fun stuff :-(

I will try to figure out the dwgs and trouble shoot the circuit...I'll report back asap...Thx...

[911 tweaks]

I do know this...when I put my meter on the 2 terminals where the engine bay lite rests on, I have 0 volts...w/ & w/o the parking lites on & w/ & w/o engine running...

So this T6B thingie...terminal 4...rt rear side of engine bay...should I have power or gnd there...??

[Targa Time]

I had the exact same problem with my lights. I had a dead short at the engine bay light. You can see from Bob's schematic that it is part of the circuit. Disconnect both wires at the bay light, make sure they are not grounded, and try a fuse in the circuit again. That would be the simplest way to check it without isolating the parking light circuit.

Good Luck

[Bob Kontak]

Brown is always ground. Power comes through the green wire.

[Targa Time]

If you are not going to trace the wires never assume that the color is correct.

[Bob Kontak]

Originally Posted by 911 tweaks

BK...I was hoping you were onto something = I closed the engine bay lid ie rotated its cover closed which should cancel it out of the circuit, no...??

It depends on how the light grounds. If there is something in the light that grounds the green wire to the engine lid (through the light housing) , rather than through the light bulb and then through the brown wire you will fry fuses all day.

[Bob Kontak]

Originally Posted by Targa Time

If you are not going to trace the wires never assume that the color is correct.

Good point. Peeps die making assumptions.

[Bob Kontak]

Disconnect the wires like TT says. Don't let them touch anything. Turn your parking lights on. Put your multi meter to DC voltage on like the 20 volt scale. Put the red probe to the green wire and the black probe to and engine ground. You should have something close to 12 v.

Do the same with the brown wire. You should have no volts.

Switch the meter to resistance - the audible setting - touch the leads together to hear the sound. Touch either lead to the brown wire and the other to engine ground. You should hear the tone loud and clear.

If this checks out - focus on the light and how it is wired.

[911 tweaks]

Bob you are the man...I originally thought the lite was hard wired = I would have to cut the wires but I found how to remove the cover...then I removed the 2 wires...turned on the parking lites & put the meter to the 2 leads & it has 11.8v...nice...
Now, I need to figure out why the actual lite itself is shorting out causing the circuit to pop...
Any ideas on the actual lite...?? It does appear to be tired = it is a bit loose when you rotate the barrel of the lite...I also notice that if you over rotate the lite beyond a certain point, you go over the contact areas & it appears that the unit may gnd out then...??
I have a car battery on the bench that I will use as +12v & my meter & see whats up...
Thx a bunch guys...I'll let you know what I find out...
Bob

[Bob Kontak]

Cool beans.

Don't forget my wired backwards theory. Green goes to the side without the light bulb.

[911 tweaks]

thx & I want to post a pic of the unit...it appears to be missing a round disc on 1 side...are you familiar with what these lites look like inside...??
As for the wired backwards, how can I tell which side of the lite gets brown.gnd wire & which gets the grey 12v wire...??
Pic coming in a minute...stand by...

[911 tweaks]

here we go...is the side w/ the pen sticking thru it missing a dics ~ insulator like the opposite side...??
Also, the pen side looks like the gnd side or does it not matter...?? the brown wire/gnd was attached to the opposite side of the lite...

[911 tweaks]

there we go...what do you think...??
Thx, Bob