Why is only my passenger taillight out?
 

My passenger side rear taillight is out--both parts, rear and side. Turn signal and brake lights work though. The bulb filament looks good though. What would cause just my passenger side rear tail light to be out? 1974 911
Thanks!

Tail light issue.
 

Just a guess, but you may want to have a look at the 6 pin taillight connector
for corrosion & voltage check.

Good luck,

Gerry

pm me as needed.

Check the grounds

I would not try to determine if a bulb is good by looking at the filament.

You need a voltmeter and you need a wiring diagram. A bulb is cheap, buy a new one and try it. If its not the bulb start troubleshooting in an orderly manner. If the bulb is good either you don't have 12v at the socket or you've lost your return (ground). Check for 12v at the socket. If you don't have it, check for voltage from the fuse. If you have 12v, confirm the return wire has not come loose or corroded at the connector.

I'm guessing it's not the bulb. There's a low probability two go bad at the same time unless a short blew both simultaneously.

Again if you're going to do troubleshooting you've got to have a voltmeter and the correct wiring diagram for your MY car.

I had a problem with my 86 once where one side of parking lights went out. I suspect it was a broken connection somewhere. My solution was to trace the wires with a wire diagram and jumper the bad side to the good side so both ran off the same circuit. Worked like a champ unless you wanted to use the parking feature where you light one side with the turn signal lever when the engine is off.

-Andy

So I just checked and I'm not getting 12v to the socket on the rear passenger side tail light. But it's odd because the brake light--that runs through the same socket--does work. I attached some pictures here. To make this matter worse, my front fuse box is an absolute mess. It looks like something out of WWII. The PO installed an alarm, some ridiculous automatic turn-signal gadget, and a bunch of in-line fuses that don't make any sense. I have absolutely no idea where to even begin looking at the front fuses for this tail light. Any suggestions where to start? It's a 1974
http://forums.pelicanparts.com/uploa...1352952992.jpg
http://forums.pelicanparts.com/uploa...1352953023.jpg

HWM,

Hope you are well Brother!

Okay, I see your brake light is working so it appears to be at the fuse panel. I say this because if it was the ground your brake light would not work.

Check the wires going up to the panel to see if any are loose or dropped out, if so you have found the culprit.

Just note wires going in from the top are the 12v in and the bottom outs are to the component/switches.

Jim

How about a picture of the WWII fuse box?

Might be time to get a wiring diagram and start returning it to stock, removing said alarm...

Chuck.H
'89 TurboLookTarga, 342k miles

Here's my fuse box. It's been like this since I bought the car several years ago. I took sort of an "ain't broke don't fix it" approach to it, even though I knew it was a clusterF of wires that I didn't need. The second picture...I don't even know, just a bunch of grounds with a thick piece of foam board underneath? This fuse box should be a whole new post in and of itself...
http://forums.pelicanparts.com/uploa...1352999350.jpg

http://forums.pelicanparts.com/uploa...1352999376.jpg

Can anyone tell me what fuse I should be looking at for the passenger-side tail light? I can't find a wiring diagram for a 1974. I am still trying to diagnose why my PS tail light won't work. There must be either a fuse or ONE wire worn out, as all other lights in the tail cluster work.

This is nothing more than my 2nd guess.

Your fuse panel appears somewhat similar to our '86,
however, the three 8A (white fuses) should be 5A (yellow) fuses.

However, someone has played some serious "fingerpoken" on this panel!!!!

Here:

http://forums.pelicanparts.com/uploa...1353090735.jpg

http://forums.pelicanparts.com/uploa...1353089755.jpg

http://forums.pelicanparts.com/uploa...1353089962.jpg

Rotate & check for voltage on both sides of this fuse.

Here are a few links:

http://www.2010.cannell.co.uk/manuals/manuals_porsche.html

https://www.google.com/search?sourceid=navclient&ie=UTF-8&rlz=1T4GGHP_enUS433US433&q=porsche+911+electrica l+manuals

pm me as needed.

Good luck,

Gerry

So I checked the wiring bundle at the rear light cluster and everything seems to be ok. No broken or exposed wires. The tail light socket is not getting 12v though when the lights are on. Brake lights work fine on both sides.
I checked the front fuse box and again don't see any broken wires. All fuses look good. I checked the voltages, but here's the main problem...I don't know what fuse is actually for the rear tail light. I looked at the one listed in the above diagram but it didn't match with my car exactly. Compounded by the fact I know NOTHING about the electrics on this car, I am completely lost on trying to figure out why my passenger side tail light doesn't work. Any further advice or tips would be much appreciated. Thanks guys...I know this isn't as sexy a topic as HP increase or a suspension refresh but I can't my car at night now for fear of getting pulled over...

As Gerry suggested: check the fuses on BOTH the input side, as well as output side...all of 'em....report back. If you've got 12 volts on one side, you should see the same on the other side of the fuse...


BEST

Doyle

The Haynes maual shows a gray/red wire that should feed from the bottom of fuse 1. The lettering in the manual is so small amd looking at it through a magnifying glass.
Do you even see a gray/red wire coming from the front fuse panel (bottom part)?

I had a similar problem on a project car. I would start by taking off the 6 pin connector in the back right corner of the engine bay and get a voltmeter with a connectivity buzzer and start checking my wiring connectivity working back from the light socket, to the the female connector, then from the same pin on the male connector to the front fuse panel. you have remove the wire from the fuze panel in order to ensure it isnt getting connectivity from another source. then put a small piece of tape on each one and start determining what wires go to what. Then create your cars wiring diagram. sounds long and tedious...and it is...

you can start with the wires that go through to the rear. Just below the gas fill pipe, there is a hole where the wires from the front feed back to the rear of the car through the main harness. and it looks as if this circuit does that. in the back of your engine bay, right front section, the wires from the main harness come through and some go to the right (and the 6 pin connector and the some go the left over to the 14 pin connector (ands the 6 pin for the driver side light bucket). surely possible you have a single line with has broken in the middle someplace but you wont find it unless you start checking connectivity.

One way to verify the bulb works is is to run a good wire from the 12v source to the right pin on the female connector...at a min, can help you find out which one it is...

The reason the right brake light works is it comes off a different fuse (fuse 11). It also runs from the fuse, to the switches on your brake system, then to the rear...

My suggestion was not the bulb really...you can obviously swap that to verify it is working. But once you locate the right pin on the female connector, you can run 12 v to that pin and then start eliminating the light bucket as the problem.

The problem could very well be in the bucket itself. there are two metal pieces in the socket. One might not be pressing up against the back of the light bulb. take out the socket reach in there and make sure they are both touching the bulb. The back of the bucket can be removed to look at those also. Again, part of the suggestion to run a new wire to the correct pin and ensure the bulb lights up. hope that helps...

I am having a similar issue but I think it is my connectors on the back of the tail light housing. If I "push" the bulbs in deeper into the socket, they come on full. If i tap them, they go out. I thought I had a short or bad connection, now I am starting to think the connectors are just aged and need adjustment. My problem now is the screws that hold the housing into the car are a bit old and NOT cooperating.... I really dont want to drill them out...

Robin, your situation is most like the pcb plate is fractured ans not allow proper contact. You need to get in the light assembly and repair it with a piece of plastic and glew it down.

Once fully broken the hot lead will touch the housing and it will cause havoc to your brake system and mayburniut yourbrake light switches in them mc. Ask me how I know :-(

You can reach into the socket with a small tool and bend the two metal pieces toward you...I did the same thing and it worked fine. they will then press up against the light bulb..

+1. I've also discovered that the soft metal contact at the bottom of the bulb often becomes flattened and creates issues similar to that described by the OP, even if the filaments are fine. Switch or replace bulb.

So this a very late follow-up to the problem I had in the first post, that as of now is still unresolved. My passenger side tail light doesn't work. It's not the bulb. Bulb has been checked and known good bulb doesn't work in the socket either. So far, this is what I've done:
http://forums.pelicanparts.com/uploa...1406156544.jpg
http://forums.pelicanparts.com/uploa...1406156691.jpg
Checked the voltage at the socket. Only getting ~1 volt at the socket. Weird part is, after pulling the wires from the socket I checked the voltage straight from the wires, and it jumped to 6.43. That happens to be exactly half the voltage I need. I wonder if there's something to that.
http://forums.pelicanparts.com/uploa...1406156882.jpg
I've checked the voltages at the fusebox and all seem to be at ~12-14 volts at the top and bottom of the fuses. http://forums.pelicanparts.com/uploa...1406157090.jpg
Can anyone make anything of this? Bulbs are good. There's obviously not enough voltage to the socket. But if the fuse were blown or bad, NO voltage would be getting there, right? How would I check continuity from the tail light all the way to the fuse box with my little multi-meter? Any help is greatly appreciated. Thanks!

Fuses do go bad. Try swapping them with the good side and see if the good side goes out and the bad side lights up. Yeah its a long shot but it's quick.

This is half of the schematic and legend for the 1973 and should apply to your vehicle. The whole schematic is available from our host on this web site if you need it.
http://forums.pelicanparts.com/uploa...1406169099.jpg

http://forums.pelicanparts.com/uploa...1406169122.jpg

You can copy both pictures to your computer and enlarge them to see the circuit. The luggage compartment fuse panel consists of two fuse banks the first has 8 fuses and the second has 10 fuses. The legend indicates fuse six on the bank of 8 fuses supplies power to the Legend 19 (rear light and side marker light) using a wire with the color code of Gray/red (the red is the stripe).
If you are using a volt meter and reading battery voltage ~12 volts at both sides of fuse 6 to ground and then are reading ~6 volts to ground at the disconnected contact to your right rear light and side marker light then you have a high resistance somewhere between the fuse and the contact at the light socket. There is only one multi-terminal (6 contacts) between the fuse and the light contact terminal. This would be the most logical place for the high resistance to occur. Disconnect the six pin connector and try to ascertain which pin is the Grey/Red wire. verify that you have ~12 volts at the pin. If you have the ~12 volts and the contacts are clean then re-mate and check the light contact again.

my preferred method of troubleshooting is continuity testing with a multimeter, you can pull the fuse and using a long lead do a resistance check from the load side of the fuse in the luggage compartment to the light terminal at the rear of the car. You should see a low resistance ~0 to 5 ohms. if you see a high resistance you can recheck the terminals at the fuse, multi terminal connector and at the light contact. moving the wires may give you a visual indication on the meter where the problem is located.

The long lead can be made up from a wire with two insulated alligator clips (radio shack has the parts). I have had two 10' cables in my tool kit for the past 40 years. One is red and the other is black with insulated alligator clips on both ends. They come in handy to jumper out any wire in a circuit or to do resistance tests between to distant points. The continuity check is the method I used to verify my wiring harness circuits before applying power as I re-installed them into my 80SC.

So fuse 6 in the bank of 8 has the gray/red stripe wire. I checked again and it has 12 at *the bottom* but isn't registering a voltage at the top. But a lot of the fuses weren't registering a voltage at the top. I swapped out fuse 6 anyway but still no light in the back. I tried looking for the 6 wire connector but can't find anything inside the luggage compartment that looks like it. There is a silver box deep inside the cowl area, just behind where the oil level gauge would be on the dash. I took a picture, is this it?
http://forums.pelicanparts.com/uploa...1406176144.jpghttp://forums.pelicanparts.com/uploa...1406176206.jpg

Why is only my passenger taillight out?
 

The lighting harness wires run directly from the front fuse panel through the car to a six pin connector in the engine bay with no other connectors. It is to the left of the rear motor mount for the left side tail lights.



The running light wires run first to the driver side lights and then doubles back through the main harness over to the passenger side. You may have a break from the driver side to the passenger side.

http://img.tapatalk.com/d/14/07/24/agumy5e8.jpg

If you want the correct color coded electrical drawing for your car, PM me your email address and I will send you a link to my files on Dropbox.



http://img.tapatalk.com/d/14/07/24/8yme2ete.jpg

Sorry , I should have been more specific on the location of the 6 pin connector located in the engine compartment. If you read 12 volts to ground on one side of a fuse you should also read it on the other side. It should be noted that you need to have the key in the ignition to on and the light switch to the parking lite position to check for the correct voltage of this circuit. Verify that one side of the fuse has the gray/red wire attached. The information I have indicates that the schematic that Timmy2 has provided is for a 1978 series 911 and the one I provided is for a 1973 series 911. The 78 schematic shows fuse 3 as the one for the rear lights, where as on the 73 schematic fuse 6 is the supply. You need to locate which fuse has the Grey/Red wires attached and go with the schematic that corresponds to your wiring. In most cases, the wire color coding has stayed the same throughout the model years. but the fuse being used has changed i.e. in a earlier post for a 89 series used fuse 1 for the parking lights.

i just looked at my car and i have two grey/red wires. one is from the light switch to fuse 3 supplies 12 volts when light switch is on with ignition on. and the second wire is on the other side of fuse 3 going back to the light assembly.Once you locate the grey/red wires I would suggest using the continuity test with a multimeter to isolate the wiring and locating the problem.

there is also one other check the 911 has a european feature that when you park the car and shut off the ignition but leave the directional signal in the left or right positiion the parking /side marker lights for that side will illuminate. due to the narrow streets in europe this allows on coming cars to see that a car is parked on the side of a road at night.

Targa80,
Zoom in on the picture of the schematic I posted. It clearly states it is for a 1974.
Similar to the '78 but different in many ways.


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Thanks for all the info, I tracked the problem down to the 6 prong connector in the passenger side of the engine bay. There's a short of some sort in there, as I can wiggle it and it will work for a second, then goes back to dead. I also realized in the removing the backing plate of the tail light socket that the bulb now doesn't seat against it very well. So between those two things I think I can get this light fixed. Don't know how I'm going to attack the short in the connector though...

Hotwatermusic,
PM me or email me and we can come up with a solution for your connector.
I can either have you cut yours off, send it to me to repair it and cast a new rubber molded plug for it, or make a new one for you to splice in replacing your old one. I would want your old one for parts either way.
I can give you precise instructions and supply quality parts for Splicing it back together.
Here is a picture of a connector I made.

http://img.tapatalk.com/d/14/07/25/7u2ugy4e.jpg



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Why is only my passenger taillight out?
 

Factory on the right, mine on the left.
http://img.tapatalk.com/d/14/07/25/3ugy6y7y.jpg


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Timmy 2 ,

My apologizes you are right, your schematic is definitely for the 1974 and not the 78. I should have look closer.

SmileWavy

No problem, the OP hasn't responded to my offer to send him the real print for his car or to help him with his busted up 6 pin plug. Go figure...


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I'm here! I just had to work today and couldn't respond. I wanted to examine the connector a little more before asking for further help, just to see if the problem could be fixed here. Believe me, I am not taking the knowledge and help available on the this board for granted. I will report back ASA I know exactly what is broken.

Lol, no problem HWM that work stuff is what let's us afford this madness. :)
If the failure is actually in the 6 pin connector you are dealing with a broken or cold solder joint or a broken pin. The pins are soldered to the ends of the wire before they are cast in the rubber connector and the white plastic alignment guide is installed.


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Any solution to this? My 78 just decided to do the same thing!

My car had the same issue. Issue turned out to be a mess. Totally destroyed the harness which goes through the tunnel.

http://forums.pelicanparts.com/uploa...1446842328.jpg

Reviving this old thread since it just happened to me. I have tracked it down to the Grey/Red wire from the female side of the rubber plug. Jumpered from tailight to Male side, lights work again. My reason for reviving this thread is now how to fix this with the molded plug. Does Timmy2 still make these? Thanks all.

Re-reviving this thread because this just started on my 86. Symptoms are right side front marker and right rear tail light stopped working outa the blue. So far confirmed the fuse is good and breaking out the multimeter to begin diags. I did purchase new light weight housings so save about 10 lbs and will be converting to those for now as I refurbish the original housings.

Next move is check voltage on fuse 6 on top and bottom. Anyone have additional suggestions?

Thx

Kevin

Update. Fuse 5 (working left side) 13v, Fuse 6 (non working right) 1.8v (both top and bottom of fuse). What on earth could cause that? Faulty light switch since that’s the next upstream component?