Author Topic: Tail light conundrum  (Read 8514 times)

frankenbenz

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Tail light conundrum
« on: May 29, 2013, 13:18:29 »
OK ... here is a minor frustration, but frustration nonetheless.

For any of you who have followed my FrankenBenz project, you'll know that this car is anything but "original". I am currently in the position of buggering around with the tail lights.

For some reason (probably many reasons given what I have done to this poor old car) my tail lights are a little confused. When the car was completely rewired for my nefarious purposes, somehow the tail lights got it in their little electrical head that when I step on the brakes, the amber portion of the light will come on as well as the brake lights. I put the amber version of the tail lights in thinking it was a much better look for the car I was building. The turning indicators work fine. The backup lights work fine. The brake lights work fine. The tail lights work fine at night. It is just this weird little quirk that is throwing a monkey wrench in the works. (by the way, if this is also a clue as to what is happening, the license plate lights only come on when the brake is on also.

Now, a solution for the brake/turn signal problem would be to replace the amber style lens with an all red lens. I have spoken with people who sell repro all red lenses, but they tell me that their lenses won't fit the reflectors I have. I have the plastic bulb holder and I am told I need the metal bulb holders as well as new reflectors. All in all, a pretty pricey gambit when all I really functionally need is a set of all red lenses.

So, the ultimate question here is ... what are the consequences in using all red lenses with my existing bulb holders and reflectors? I'm obviously not averse to doing "unusual" things to the car. But what is it about the all red lenses that would be such a catastrophe if I were to try to mate them up with my existing reflectors and bulb holders? Not having a set of red lenses in my possession, I can't see what the big deal is. I am told that the backup light part of the lens is different on the all red lenses and the amber style lens. So what? Functionally this is not a big deal for me. Asking the people who are selling the red lenses results in absolutely no response.

Can somebody please explain the situation to me like the relative 8 year old that I am in this situation? If the lenses physically fit and fit over the existing reflectors and have the bulbs in approximately the same position, what's the big deal?? I just don't want to spend a couple of thousand dollars where I can spend a couple of hundred if I end up with the 98% solution.

Ideally, I would have liked my electrical guy to have figured it out, but there have been several people involved in the wiring of this car, most of whom are no longer reachable with the last guy telling me "the problem is up front, not in the back" meaning the way the car was wired, he believes that both the brake lights and the turn lights were somehow connected together somewhere even though the red part of the tail light does not glow red when the signals are engaged, however the amber part of the light does light up when the brakes are applied.

I have attached a photo of my current lens, bulb holder and reflector. To me, it appears that I should be able to simply swap out the red lenses with the amber version lenses and, with more than likely a little light leakage from the backup lights, it should be easy-squeezy. I don't really care if the signal part of the light comes one when the brakes are applied ... red lights are red lights. But amber coming on when the brakes are applied, to my mind, is not cool.

Now remember .. this is NOT a Mercedes 113 wiring harness ... this is an aftermarket wiring harness necessary for all of the modifications done to the car. I know there are those of you out there thinking "yeah ... it serves you RIGHT for what you did to this car". Understandable, but not helpful :)

Hopefully this made some sort of sense to someone out there.

Thoughts??

mdsalemi

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Re: Tail light conundrum
« Reply #1 on: May 30, 2013, 19:46:46 »
My own opinion is you (or whoever is working on this) is looking in the wrong place.

Since the car was "rewired" we can't rely on what is "supposed to be" but let's think about this for a second.  When you hit the brakes, you close a switch, and that switch activates the brake lights--which on my assembly, are the inner lamps on each side. The amber portion--the outer--are directionals, and only come on when activated by the directional switch.  The tail lamps--red--come on when the parking lights/head lights are on.  The final lamp--backup--is engaged when you are in reverse. These are all switches in the front of the car, going to fuse points, etc. then to the harness that goes to the back.

In your case, you have the amber directional lamps coming on when braking.  I assume that no other lamp comes on when it isn't supposed to, and all others do come on when they are supposed to.

Well, if you found someone who wired it incorrectly, why not just wire it correctly or find someone who can?  Even if you have to run additional wiring ex-harness inside the car (under the carpet) why not try to get the wiring correct?

I'm talking glaring generalities here; there are different wiring diagrams for different cars, and it seems that someone should spend the time to get it right. I'd suggest a hot rod shop that specializes in extreme conversions...they are used to this kind of troubleshooting.

Going with all red is kind of a strange solution...

No I am not going to chastise you for all this crazy work, but it lays bare the old adage that "the devil is in the details".
Michael Salemi
Davidson, North Carolina (Charlotte Area) USA
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frankenbenz

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Re: Tail light conundrum
« Reply #2 on: May 30, 2013, 19:57:00 »
Thanks Michael ...

You're right about the devil being in the details. Satan may not live full time in this car but he certainly makes it his vacation home. I have a decent wiring guy and he'll have to get into it. He was hoping it was simply a crossed wire in the back but it was not to be. Running down problems like this is a huge pain in the butt given all of the interior stuff that has been done to this car. Ripping everything back out again would be a very expensive nightmare, hence the thought of simply using a red tail light lens. I'll keep the board posted on what is going on. It is currently in the shop getting the fuel injection issues sorted and will likely stay there for the next few weeks while I'm away. The current shop would be better utilized for things such as brake issues and perhaps installing power steering. This thing is a **** to parallel park!

Back to the grind ...

mdsalemi

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Re: Tail light conundrum
« Reply #3 on: May 30, 2013, 21:15:06 »
Without knowing what was done, I suggest you don't need to rip anything out.

Your good wiring guy simply needs to determine how and where everything is working in the front: the switching that controls brake lights, tail lamps etc..
He has to find where these end up in this new harness, and test this at the front of the car.
He has to find the end of the harness at the rear and retest there.
Even if something is shorted or crossed in the harness, you can simply bypass with new wiring and leave what is, there.
The scientific method applies...

Sometimes in pursuit of the minimal amount of work, we/you/he will spend an inordinate amount of time. Get back to the beginning and track it all down from the front of the car.

In the end you'll be glad you did and got it right.  :)
Michael Salemi
Davidson, North Carolina (Charlotte Area) USA
1969 280SL (USA-Spec)
Signal Red 568G w/Black Leather (Restored)
2023 Ford Maverick Lariat Hybrid "Area 51"
2023 Ford Escape Hybrid
2024 Ford Mustang Mach Ex PEV

frankenbenz

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Re: Tail light conundrum
« Reply #4 on: May 30, 2013, 21:18:03 »
Solid advice ... I'll let you know how it turns out!! Meanwhile, any insight as to why all red lenses won't work with my existing reflectors and bulb holders? That makes no sense to me at all ... :/

66andBlue

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Re: Tail light conundrum
« Reply #5 on: May 30, 2013, 22:02:39 »
My guess is that your bulb holders are the late style whereas red/red lenses only fit the early style holders.
Take a look at the photos here: http://www.sl113.org/wiki/Electrical/TailLights
Alfred
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frankenbenz

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Re: Tail light conundrum
« Reply #6 on: May 31, 2013, 00:05:20 »
Hi Alfred ... I'm sure you're correct. But my question is, what is the catastrophe of buying the red lenses and using them on the other reflectors and bulb holders. They must physically fit the metal frame ... and while the reflector and bulb holder are not "correct" for these all red lenses, my ultimate question is "so what??" There are 4 lamps in each version. I know that the "white" portion is a different size with the all reds than the red/white/amber, but again ... so what? I guess without spending a butt load of money, I'm looking for someone to tell me ... A) will these various parts all "fit" together ... if not, why not ... and if they all fit together, what are the consequences of the red lenses with the "amber" version holders and reflectors?

No one has yet been able to tell me what the big problem is. If I had a set of red lenses I'd try fitting them together to see for myself what the issue is and may well find that the combination is physically impossible. I'd be fine with that. But if it isn't physically impossible, I'd like to know what the issues are. From those who have seen this car, it's easy to know I'm not opposed to "engineering" around things that are supposed to fit. In fact with the lenses that I currently have, they were bonded to the reflectors. 10 seconds with a grinding tool and they no longer were - all without damaging the reflectors or the lenses ... all to say, is there ANYONE who can tell me what the big deal is?

Thanks gang!!

Garry

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Re: Tail light conundrum
« Reply #7 on: May 31, 2013, 02:58:47 »
I don't believe there is a problem with putting the all red lenses into the other frames but what you may get is some light spill from the centre upper portion to the lower portion if they are two different sizes lenses between the white and the red portions. Easily fixed by fitting extra baffles into the holder.

I have looked at several different types of tail lights I have here including the different holders and that is the only consequence that I can see happening.

Garry
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frankenbenz

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Re: Tail light conundrum
« Reply #8 on: May 31, 2013, 08:24:24 »
Thanks Garry ...

This has been my contention ... but without having a set of all red lenses to test that concept, I have been very hesitant to throw down a few hundred dollars to test that concept. I am absolutely not above building baffles to keep the "spillage" in check.

If anyone else can confirm Garry's thoughts that would be awesome. Ultimately, I would love to have my wiring guy figure it all out. But should the worst case scenario persist and I need all red lenses, I would like to know that with some simple modification to prevent light leakage or spillage from the top "red" section into the white "reverse" section I will be OK .. again, there isn't much that is standard in this car. I'm not about to hold to being a purist with the tail lights!!


pj

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Re: Tail light conundrum
« Reply #9 on: May 31, 2013, 09:05:58 »
I fiddled with my tail lights recently and I was struck by how even a tiny difference in angle or alignment of the bulb holder unit has a big effect on where light spills around the edges built into the reflector. It's another example of delightfully complex design. I imagine all car tail light units are like this.
Peter J
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frankenbenz

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Re: Tail light conundrum
« Reply #10 on: May 31, 2013, 15:33:18 »
Thanks PJ ... I'm pretty sure I 'm going to have to do some custom baffling inside these things. If the worst case scenario is that there is a little red "spillage" when the reverse lights are on I'm totally OK with that given the rare occasions I need to back up in this thing. I'm way more concerned about what I have now which is the amber section fully "on" when I press on the brake lights. Quite annoying!!

Thanks everyone for their input.

Garry

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Re: Tail light conundrum
« Reply #11 on: May 31, 2013, 23:58:26 »
Are you saying that the amber section as well as the brake section is lit due to both tights going on or just from light spillage.

If it is both then what comes on when you use the turn signal?  Maybe you have a wiring problem?

Garry
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Melbourne/ Kyneton, Brisbane. Australia
1969 MB 280SL 5 speed RHD SOLD.
1965 MB 230SL Auto RHD Lt Blue 334G, Top 350H, Tourist Delivery.
1972 MB 280CE Auto RHD 906G
2005 MB A200
2006 MB B200
2019 Izuzu DMax 4x4 Slide-on camper.
2022 Volvo XC40 Electric
2024 Volvo EX30 Electric

Palolo

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Re: Tail light conundrum
« Reply #12 on: June 01, 2013, 07:11:57 »
Frankenbenz, you have a ground disconnected somewhere back there.

The brake lights are pulling a ground connection though the turn signals.

Look around the ends of the rear wiring harness where the plugs connect to the tail light harness. There is. Separate wire which you need to ground, typically to a screw just to the side of the area where the rear harness connector is.

You can identify which one it is by following the "common" wire that snakes rom bulb to bulb in the tail light, then follow that up to the rear harness.

Good luck,

Pat

frankenbenz

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Re: Tail light conundrum
« Reply #13 on: June 08, 2013, 23:15:53 »
Thanks Pat ...

I get back to town in a couple of weeks and will take the car over to my wiring guy with your information. Hopefully this is the simple fix.

Garry ... yes, I'm sure it is a wiring issue and definitely not spillage. I have been away for a couple of weeks and the car has been in the shop trying to sort out the engine issues. I got a call on Friday saying that the engine issues have been resolved. That was the REALLY big issue with the car. They had to replace the whole computer that is running the thing right now as well as the throttle position sensor. But I am told it is running like a top now.

Next mission, try to figure out whether or not I have the room to install a brake booster and to isolate a loud clunking sound coming from the right rear quarter panel. By hook or by crook I will have a 100 point car by the end of all of this and I WILL be driving this thing over the summer. 20 years is long enough! Time to enjoy the ride!

Ben

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Re: Tail light conundrum
« Reply #14 on: June 21, 2013, 12:36:35 »
I would also suggest checking that you have the correct bulbs installed. Sometimes a dual filament bulb fitted where only a single filament should be can cause this effect.

Also the problem with the tail lamp lens/bulb holders is that the sidelight bulb is in a slightly different place, its fixable though.

frankenbenz

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Re: Tail light conundrum
« Reply #15 on: August 22, 2013, 02:55:50 »
Alright gang .. problem solved. For all the brouhaha over red lenses vs red/amber lenses and light "leakage" and right vs. wrong reflectors and right vs. wrong bulb holders ...

I was able to get my hands on a brand new set of all red lenses. These came from a guy in California that goes by the name on eBay as Benzrestorer. I think his real name is Babook Baloori or something quite similar.  Well, today after getting back into town and retrieving the FrankenBenz from it's favorite place (the mechanic) I was able to simply install these all red lenses and my problem is solved. The white part of the lens is absolutely identical on both types of lenses. I have no idea if this is a new version of an aftermarket lens or if this is always the way it has been. But the issue I was having - the amber part of the lens (the turn lamp) coming on when the brakes were applied is no longer an issue. When I apply the brakes now, the center brake light part of the lens illuminates as does the section with the turn lamp. So I have two red sections lit (three if I have the headlights on). And when I apply a turn signal, the outmost section flashes. This completely resolves my problem. I didn't have to change out the bulb holders or the reflectors. I just swapped one lens for the other. Of course I had to grind out the "melted" section of the lenses - the four little teats that when melted hold the lens and the reflector together - but this was an absolute non issue.

So for others who might be all flustered about swapping out amber lenses for all reds, I am a living example that it is very easy to do.

One problem solved .. several yet to conquer. Off to bed.

Thanks for all of the input on this topic.