Turn signal always illuminated when headlights on

You talking to me? Wouldn't it be the one with the single L (blue) wire going to only one side of the turn signal bulb?

Those voltage measurements could also be made at the terminals of the turn signal bulb if those are easier to touch with the multimeter probe when everything is plugged in and running.

 

Sorry, I meant to say from pin 9 to other pins.

 

I can't be sure if the wires aren't twisted at the back of the plug in the photo or if the numbering system is not standard. I came across a Ferrari plug recently where the numbering was

1 3 5 7
2 4 6 8

 

Correction... it was like this....

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USA seat belt/door warning buzzer (328, 348, F355, 456, 512, Mondial, Testarossa)

 

Yes, the far outside running lights on both sides (the lights right above tthe yellow turn signals) flash dimly when the RH blinker flashes.
Only when side lights are off. When sidelights are on the RH turn signal is fully illuminated and nothing flashes.

I was thinking that if that fuse blew while I was changing the license plate lights I'm going to take a closer look at the wires to that tonight. Power was off when I changed that bulb there isn't any reason for that fuse to blow unless there is a hot in that wire????

 

Please clarify: Does the rear right blinker (orange) light come on when you switch-on only the Parking Lights (only the outer of the three small bulbs in the rear lamps come "on") using the "P" button on the console switch cluster? (keeping the lights stalk switch off)

Did you check whether your rear right blinker light still comes on when you test with the flasher relay/module unplugged? Ian asked this earlier but I see no feedback from you.

 

I have not done anything with the "P" switch. I have only turned on the lights wiyh the switch on the steering column.

Which is the flasher relay?

I did pull every single relay with the emergency flasher switch engaged and they never stopped flashing.

I will let you know about the "P" switch when I get home this evening.

 

Not sure. On the 355 it is located in the driver's footwell (door side), just above the carpet line, but the 348 may be different

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This is making less and less sense. All the running are connected to each other in one way or another. If turn signal voltage is jumping to the running lights, it would make all the running lights flash. Even the dash lights would flash. Having said that, the turn lights would probably stop flashing or start hyperflashing due to too much resistance in the circuit from additional lamps. Are the running lights on the side of the car flashing?

Something else to try when you've tried the other suggestions... Disconnect the plug on the RH rear lamp assembly and turn on the RH turn. Does the LH rear running light above the LH turn light illuminate as it did in your previous test? (the turn signal may stop flashing or hyperflash). This may tell you if there is a problem in the RH rear light assembly.

 

On my RHD car, it is just below the dashboard, to the right of the steering column. You can also switch the indicators on and locate where the clicking is coming from.

 

I have been through the tail light assemblies. Like I said I don't much understand electricity. But I checked every wire and socket for continuity and shorts. other than those two things what should I check for? I did see wires in about 3 spots that were questionable, as they looked like they had been smashed somewhere along the way. I spliced soldered those questionable areas.

But still in my mind any of the afore mentioned issues would cause lights not to work. Not, come on all of the time.

After this comment I thought about replacing the assembly. it is 2700.00 euros. I'll take it to a professional electrician before I do that. I am about ready to give up and take it to an Electrician but I have got it in my head that I really want to beat this. I can't let the Gremlins win; can I?

 

All you can do is isolate various parts of the turn and running light circuits to see if the problem goes away or changes in nature.

Do you know if the light assemblies are interchangeable? Have you tried interchanging them or are they difficult to remove? On paper, they seem interchangeable, despite the lenses being the wrong orientation.

Did you find the earth near the radiator yet? In some respects it doesn’t seem like an earth issue, but you may have a combination of issues.

 

Replacing the whole light assembly may be a big waste of money as the problem may not be there at all. And if the problem is in the light assembly, it can only be in its wiring harness which can easily be fixed.

I happen to have a very good condition RH lamp harness which I am about to list on Ebay. If you would like to try with replacing the harness, I can send it to you (PM me).

With regard to the use of LED bulbs, I have installed them in all positions except for Indicator and Reversing and have no issues.

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I don't know if it is just because i'm getting old or this has just become so complicated that I have forgotten what I have tried already. So, last night I wrote down everything that I tried last night.

1) Swapped RH and LH turn signal assemblies. The problem is not in the assemblies.

2) Looked for short in license plate light wiring. Disconnected that pigtail. Problem does NOT seem to be associated with License Plate lights.

3) With just the "P" switch on, only got two outside red lights and the yellow one that won't turn off.

4) Even with all lights off. When i switch on the RH turn signal I get slight flicker on all 4 corners. The two outside rear red lights are flickering fairly brightly but not 100%. the two outside front lights flicker just slightly.

5) With just the "P" switch on I get all 4 corners plus the yellow light that won't shut off. But when I turn on the emergeny flashers I lose the left front outside running light.

6) Pulled flasher relay. None of the turn signals will flash. Yellow light still illuminated with engagement of either the steering column switch or the "P" switch. Except when I use the "P" switch I lose the LF outside running light,


I'm wondering about that "P" switch, Since it runs the two outside rear red lights and those flicker pretty strongly when I turn on the left blinker????

No, I have not yet checked the ground but I had run a jumper from the black wire on the RH tail light assembly direct to the negative battery terminal. I figure I need to get the car on my lift and remove that inner fender. I just haven't gotten around to that yet. My lift and my other cars are about 5 miles from the house, I have just been to lazy and am just tinkering in my garage while the wife watches TV. Actuallly I have bought entire new headlight assemblies for this 348 and got to get around to installing those. I have already fixed a long list of minor stuff on this car, and got stuck on this lighting issue. The remaining list is very short once I get this figured out.

Thanks!

 

What is that second relay right next to the flasher relay?

No, the running lights on the side of the car don't seem to flicker at all.

 

Looks like a buzzer for seatbelts and brake warning. It should illuminate the brake warning light during startup (to show you that the light is working).

Thanks. That answers one big question.

The P switch should only illuminate the outer lights (rear) and the front lights. The 348 has some crazy light wiring:
Fuse 10 handles the licence plate lights and the Left AND Right inboard rears.

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So the problem is on the outer rear light circuit (although the front lights can't be excluded because they are on the same fuses, 11 and 12). This is further reinforced by your turn signals (alone) affecting the outer rear lamps.

Are you sure you front running lights weren't also flashing (when the turn signals were on, but not the running lights turned on)?

 

Sorry, I missed one of the points in your recap. They do flash.

 

Ok, that is just plain weird. I can't even imagine what would cause that, but I'll keep looking at the diagram.

Hypothetical... If the blue and yellow wires going to the RH rear light cluster were partially shorted...

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RH Turn signals on (only):
With this short, the RH turn (rear and front) may be affected because of the additional load on the circuit. The flasher module would be trying to drive not only the RH rear outer running light but LH rear outer and front LH/RH ones too i.e. via a common link in the fusebox. However, the running light bulbs may have a significantly higher resistance than the flashers, so perhaps the load is not too great (explaining why the flashers behave normally when the running lights are turned off). What is the wattage of the turn lamps and sidelights?

Sidelights on (only): With this short, the sidelight fuses will be not only driving the front and outer rear driving lights but the right hand flasher bulbs, too (front and rear) and the turn light (on the dash). I guess there is sufficient fuse power to power the flashers on one side, but why isn't your front RH flasher illuminating (brightly with no flash) in this scenario? The front and rear RH flasher wiring is spliced together in the footwell fusebox .

So we are back to square one.

I've forgotten what happens to the system with both running lights and RH turn on.

 

[QUOTE="

I've forgotten what happens to the system with both running lights and RH turn on.[/QUOTE]

With running lights on and RH turn on. The yellow blinks and so do the outboard reds.

I think I'm gonna buy the "P" switch replacement and see what happens. I found one for 500 USD.

 

The P switch is just a switch with a backlight in it. You know it works because the correct lights illuminate. Does the "P<" light work on the display above it?

 

That has a rather strange circuit... I'm still trying to figure it out.

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Does the P< light on the display work when the ignition is on, but the external lights are off?

 

Ian, a couple of points regarding your diagrams:

1. On the tail light diagrams (L & R), you should add number "1" at the wires "RN" of the connector (reversing lights).

2. The pinout, taken from my spare lamp harness, is:

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Thanks, Miro. I'll add that to my diagram and the "1".

Shouldn't pin 7 also be red? And pin 8 yellow/black?

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(EDIT: disregard... Your colours refer to the internal wiring, not external wiring)

 

USA Lighting diagram update:

https://www.dropbox.com/t/0AMqJFcBgmHQcoWL

Euro:

https://www.dropbox.com/t/D2wHTnt0nNB3YvH0

(EDIT: Links updated to show the face of the plugs on the car harness side)

 

Regarding the lights switched "on" by the P-switch, these are Parking Lights, not Running Lights (nor "Sidelights"). I don't think the 348 had running lights from the factory. Maybe added by dealers for some markets? This is the arrangement of various lights, taken from the US version of the "Technical Manual" (Owner's Manual):

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The Parking Lights, front and rear, use small 5W bulbs. If there is a cross-short somewhere between the RH Indicator and the 4 Parking Lights, there would be no problem for the flasher relay to flash RH Indicators (2 x 21W + 5W) plus all Parking Lights (4 x 5W) = 67W since the flasher relay is designed to flash all Indicators (4 x 21W + 2 x 5W) = 94W in the hazard mode (ignoring the light in the instrument cluster).

Question for Chris: When you switch-on the Parking Lights only (with the P-switch), are you sure that only the Rear RH Indicator lights-up? The front Indicator light may be difficult to see in bright daylight. Double check whether your Front RH Indicator is maybe also lit-up (perhaps dim) when the Parking Lights are switched "on".

 

Not sure I follow you, Miro. Do only the (USA) rectangular lights on the side of the car illuminate when the stalk switch lights go to the first detent?

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In the wiring diagrams, the regular column light switch and the park light switch are connected to lamp "G" (left hand front corner). Note: not the G shown in your graphic, but I guess "F" in your graphic.

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