difficult front turn signal problem

[tmctguer]

for those of you who have a bent for electrical stuff:

i have an interesting front turn signal problem i am trying to solve for a 1973 911 E. when i activate my passenger side turn signal, both dashboard lights flash (incorrect behavior). upon inspection of the front passenger signals, the small bulb is flashing but the front bulb is flashing very weakly. when i activate my driver side turn signal, the driver's side dashboard lights flash (correct behavior). at the driver's side turn signal, the small bulb is does NOT flashing and the front bulb is flashing normally.

I took the turn signal light electrical connections apart and burnished them to remove all of the old buildup of crud. this did not do any good.

i have not replaced the turn signal switch yet. nor have i inspected the turn signal switch at the steering wheel.

any clues would be appreciated.

[Tomy]

Have you check all turn signal lamps all 4 as ground is the most important reason of all light problems

[pozee]

Based on a similar experience - different car...

+1 on the ground issue.

Make sure you have the correct bulbs in there. Dual filament vs. single or vice-versa will cause what you are describing.

[tmctguer]

i will double check the grounding. it is pretty basic -- a small brown wire terminated on the turn signal housing.

maybe I need to trace the brown wire to its ground termination?

maybe I should burnish the turn signal housing to make sure the ground wire has a good connection?

as for the bulbs, they are the same bulbs that have been in the car since i've owned it (2002).

thanks for the suggestions. i will keep plugging away.

[Flieger]

I think that most early 911s have this turn signal issue. At the best of times, my indicators work but the cancelling mechanism is stuck and the 2 inside bulbs in the tach both come on at the same time. Today, my left signal was working, but the inside bulbs would not come on. The inside bulbs came on when I turned the signal to the right but no outside indicator came on. The relay was clicking both ways. I cleaned up and wiggled the connection on the fuse panel in the front and this put it back to "normal"

I don't feel like chasing through the grounds just to fix the inside lights so that only 1 is on. As long as the outsides work. Inside bulbs let me know to cancel the signal but I don't need to know what way to turn the thing off.

[tmctguer]

i think i may have figured out the problem based on a posting at the Early 911S Registry website.

it appears that the bulbs in the turn signals are grounded against the housing itself (this is what was posted on the other website). this makes sense because of the brown ground wire that is terminated onto the turn signal housing.

since much of the "silver" coating of the turn signal housings seems have flaked off over the years, perhaps i need to figure out how to get a better ground between the bulbs and the turn signal housing.

[pope]

As everyone said, start with the grounding. Most common cause and easiest to fix.

The ground connection on the stalk switch itself is soldered on so this is quite likely OK and you won't need to take the steering wheel apart just yet.

The ground wire off the stalk goes to a grounding point inside the cabin under the dash near the ashtray IIRC. There's 3-4 grounding wires ending up there. Clean those fastons thoroughly (I use vinegar as per Warren's suggestion).

If this doesn't fix it, try to isolate the problem. i.e. remove the signal bulbs and see if you're still getting weird behavior. Is your emergency switch working ok?

If you DO decide to take the steering wheel apart make sure you remove the screws in the correct order. It's a flimsy assembly and can easily break - my PO hadn't handled this very well.

[tmctguer]

thanks for the suggestions. I am going to start by burnishing the turn signal housing where the bulbs are seated. Perhaps a better ground there will solve it. Next, I will go the ground point near the dash (great suggestion).

[jlex]

Had a problem w/ my left turn signal last year. Dim flashing & sometimes not working. Ran a new ground wire from the housing to the body & it's been perfect ever since. Agree w/ ground as most likely being your problem

regards,
jlex.

[tmctguer]

I burnished all the points of connection on the housings. I also inspected the grounds under he dash and they looked clean.

I tested the lights using the emergency flashers. All bulbs lit except the small bulb on the driver's side. Imoved the unlit bulb to he passenger side housing and it lit up. The passenger side bulb would not light up in the driver's side housing. The small bulb had been lit before I started taking things apart.

I double checked all fuses and all were still good. Iwull check for 12 volts at the small bulb socket, and if I have it, I will continue to look for a better ground.

[pope]

One question: what is the 'small bulb'?

[rs dreamer]

I had similar problems with my '73. If I remember correctly:

1 - If you look up into the bumper area ahead of the front wheels, the wiring harnesses from the headlights each have a ground wire that is connected to a stud that protrudes from the body. This should have a bare area that the round connector on the wire makes contact to. The PO of my car had connected these ground wires to the bumper support which was painted.

2 - Inside of the front turn housings is also a ground wire. You need to remove the housing and then remove the back white cover. Check the wiring there for corrosion.

Hope this helps. Gary

[tmctguer]

pope: there are two bulbs in the front turn signal housing, a large one that is the "real" turn signal, and a small bulb that also illuminates when signalling, but is more of a parking light.

rsdreamer: i will check the ground location in the headlights. thanks for that tip. i have already worked on the connections behind the white cover.

[pope]

Sounds like US spec

[tmctguer]

to follow up on my progress on resolving my turn signal problem:

i added a 2nd ground wire to each front turn signal housing. i grounded them at the grounding point behind the battery boxes. the ground points looked in pretty good shape, but i cleaned them off since i was adding a new terminal to them.

the good news is that i no longer get the "double blinker" on my dash board when i use either turn signal.

the bad news is that i am still trying to get the driver's side parking lamp (the small bulb in the rear of the housing) to light up. i installed a new bulb and that did not change things. i will go back into the turn signal terminals and make sure i am getting a good connection between the small bulb's terminal and the large bulb's terminal where power is connected to light the small bulb.

[tmctguer]

I just discovered something very strange about the behavior of my signals. get this:

1). with the headlights ON and turn signal OFF: both bulbs in the driver's side turn signal housing are lit. (the small rear bulb was the one that I thought was the problem.)

2). with the headlights ON and turn signal OFF: neither bulb in the passenger side turn signal housing is lit. (this should be lit just like the driver's side.)

3). with the headlights ON and turn signal ON: big bulb in the driver's side turn signal housing flashes. the small rear bulb does not illuminate and/or flash. (this is not correct, but what I thought would happen)

4). with the headlights ON and turn signal ON: both bulbs in the passenger side turn signal housing illuminate and flash. (i think this is correct)

Now turning the headlights OFF:

5). with the headlights OFF and turn signal ON: big bulb in driver's side turn signal housing flashes. the small rear bulb does not illuminate and/or flash.

4). with the headlights ON and turn signal ON: both bulbs in the passenger side turn signal housing illuminate and flash.

needless to say, this is strange.

does it sound like I have a crossed wire in one of my turn signals?

any other ideas would be appreciated.

[pope]

Make sure you're looking at the correct wiring diagram for your year: http://members.rennlist.org/911pcars/WiringDiag.htm
If it's not there, you need to locate it.

It looks like all your bulbs and their housings are working correctly (since one way or another all of them light up). You need to work backwards from there. Your lights work completely differently from mine. My flashers and running/parking lights are two completely different circuits. Yours are interconnected and I'm not exactly sure how.

So, a step at a time:
Looking at the first two points, I would presume that the connections between the light switch and the 4 side bulbs (two on each side) aren't good since only 1 of them lights up. You should check this. The light switch gives current to all 4 of these but only one lights up. It's a simple circuit and should be easy to find any breaks in it.

[pope]

...And of course you need to check the grounding on the light switch itself