LED lighting for the rear of a ‘65 Chrysler

[fury fan]

So on the heels of determining the best LEDs for the gauge cluster (here), the rear lighting also needed some attention. The harness on this car is quite odd in execution - it feeds the driverside brake/taillight, then exits the car via a large grommet-plug, feeds all the lights in the middle, then enters the car again to feed the passenger-side light. The backing lights and license light are harnessed from under the car, forward of the top edge of the bumper.

I cannot fathom the rationale for this, as there is a large structure inside the trunk that would’ve made for a cheaper, easier to install, and far more robust harness (not out in teh weather!). I think it only needed some clearance passages in some of the bulkheads in this structure, simple enough to do at design time. (and maybe that’s the reason - this was some sort of design oversight???)

While it wouldn’t have been fun to snake it through behind all those Caplugs, those big grommet-corks surely weren’t a treat to install on the harness and into the car either, and they still had to connect the tag and backing lites via those oval access holes. At any rate, the harness passes in/out on both sides where the red mark is, the 2 vertical ovals are the backing lites, and the blue circles are the brake/tail lights.

My approach is a little different - the new harness will tie into teh wiring under the C-pillar, be inside the trunk and routed on the ledge visible in the picture. I don’t think I’ll ever be carrying any cargo that would damage the harness from such a routing. And only the backing light connections might be vulnerable, as the brake lights are inside just as before (they have an eyebrow shield, FWIW).

A few years back I experimented with small LED modules to mount in the housings. This was due mostly to align the LEDs behind the fluting/fresnels in the lens (to prevent bright spots). The concern here is that replacement parts might be limited (I could stock up, though) but more importantly, these modules are mostly for illuminating advertising signs, and maybe not for vibration in automotive use. So even if I had spare modules, I might be changing them frequently, and this would require removing the top and bottom trim on the finish panel between lights, the whole light assembly, and then disassembling the light. Royal PITA!



I tinkered with 2 different module types - square and slender rectangle.

The rectangle (top) was more elegant for layout, and rather than use a PWM modulation for tail vs brake (another non-automotive part to fail) I elected to trigger a few modules for tail and trigger the remainder for braking (no add-on wiring devices needed). The square one on the bottom was just ugly overall for this purpose (and was wired for RGB, so needed a bunch of wires snipped and sealed.

I was able to make a combination of LEDs that would come on for tail / braking to where each one was behind a flute in teh lens and also give a somewhat-uniform pattern of which LEDs were on. This would have been much easier if the flutes were evenly-spaced side to side in the lens, but they aren’t. The flutes are uniform in width, but due to 2 small reflectors attached to teh inside surface of the lens - the flutes are not consistently spaced.

By electing to illuminate 3 modules for tail and the rest for brake, I had equal-to-better lighting output. I considered that the brakelight might’ve been too bright for nighttime use, but it ended up not mattering - I changed direction.

This current approach is much simpler. I cannot claim the idea - someone else on here posted a pic of something similar in a 65 Chrysler - I think maybe it was @300rag? I didn’t like it as much when I saw it, as it does not fill the lens like the modules do. But it grew on me as it would likely be successful - we must not let ‘perfect’ get in the way of ‘good’, right?




It’s a standard LED light for truck/trailer use with an oval mounting flange. Due to being automotive-rated, and made for solid-mounting, it should be trouble-free. It would still be the PITA to replace the light, but likelihood should be much lower? It does ‘suffer’ from double-lensing, but I think it should be a minimal reduction in illumination, if at all. Certainly will be better than the degradation in a +50 year-old reflector on an 1157 bulb.


When I disassembled my original lights, I found they had been ‘restored’ inside with a glued-in layer of aluminum foil, or maybe metallized duct tape. And some extra holes in the bottom - perhaps for drainage due to leaky gaskets?

So I scraped everything off, rotary-brushed them, etch-primed, and then 2 coats of generic silver. Didn’t need to be reflective in this case. And I spent only 20-30 mins on this step.

Installation of the flange-mounts was simple - using ¾” thick wood on both sides of teh LED’s lens got it centered - almost. The bottom of the housing slopes upward ever so slightly, so using the wood spacer on the top was the method I used.

One of the benefits of all this is replacing a severely-cracked license plate light. I didn’t know how bad it was - pieces were falling as I removed the 2 screws. I bought a 4-pack of these to use as forward-facing, bottom-edge-of-dashboard lights. With a little oversizing of holes, it fit nicely.

 

[fury fan]

The backing lights were the complex part of this. I initially intended to use 10-watt LED chips and heatsinks (I had an 8-pack of each on-hand) but at qty 4 per light, the wiring got too messy and visible. It was also too many little screws, and all of the heatsinks needed drilled/milled for the screws.



I found some large 50-watt chips that made for much simpler wiring and bought some larger heatsinks (which also needed milled/drilled). The wiring was slightly visible thru the original lens but was tolerable. I CNC’d some flat plates with all the mtg holes and used a V-bit to score a bending line. Due to the draft of the housings and imperfect use of the scoring lines, it took a few plates before I got a pair that would fit. Both required som tapering on the bench grinder regardless. Drilling from these plates thru the housing was done via a long drillbit that flexed nicely, so I could drill the holes that were across the housing, and fortunately the housing pierced nicely. I did 1 hole at a time to ensure everybody aligned nicely. The plates were also angled slightly downward before drilling the bottom 2 holes thru the housing.

The mtg plate acts as a heatsink, and there is thermal paste between the LED, plate, and heatsink. The wires were fairly easy to solder to the spots on the chip (I am not an expert at soldering) and are stiff enough to hold shape. The pass-thru holes are oversized and were later filled with hot glue to prevent chafing. All screws are various lengths of stainless 4-40 with nylock nuts.

Overall assembly pic:

Somehow I got the idea to put a reflector in front of it, which hides the chip, the wiring, and theoretically scatters the light better (whether that helps/hurts is unknown, though). So the reflector and heatsink got put in a cheap vise and cautiously modified in my CNC router. The heatsink needed 4 locations for locknuts. The reflector needed the white ‘background’ removed, 4 mtg holes and shortened overall. Due to the lip it would need 4 spacers (red arrow) to clear the LED and wiring (I used some ¼” tall metal ones that I had a bunch of).

Much better appearance with the reflector.

Comparison of without and with reflector:

Even though they are LEDs, the current-switching drivers (built-in) will generate heat.
So I did some timed-interval temperature tests with an IR thermometer on 3 locations: on the main mounting plate, a spot on the housing, and deep in the fins of the heatsink. After 30+ mins (turning it off briefly every 5 min to see where to check it - it’s BRIGHT) the max temps were 120°F, 110°, 140°, and were a gradual build that maxed at ~15min and stayed relatively stable afterward. The next day I put the other one on for 30+ minutes continuously and got a similar result at the end. Nothing was too hot to touch, the reflector never got warm, even, so I figure my lenses won’t melt. Although these conditions don’t exactly mimic being in the car, I figure it’s pretty close better than not checking them at all. And they’re not going to be on for 30+ minutes unless there’s a switch and/or relay malfunction.

 

[fury fan]

Now with all of this done, new gasketing was needed, so I bought a set of reproduction gaskets.
Yeah, no I didn’t, as they don’t exist.

So I looked at some narrow self-stick weatherstripping I had bought for speakerbuilding, and had a roll that was suitable. Estimated some length by ‘following’ it around the housing and added some extra. It’s narrow enough to follow the curves without buckling. The only place that needed cut/spliced was the straight vertical line. I envisioned doing some type of dovetail to keep them joined, but it’s too narrow for that. So I ran it up to the height of the other weatherstripping, pressed it to it, and snipped it flush. It will surely seal better than the dried-out crap that was on there. The lens does not overlap the flange of the housing near the screwholes by much, so the narrow weatherstrip will seal without the screws chewing into it. Weatherstripping joints on the backing light’s corners aren’t as good, but the pieces are touching each other so the pressure from the lens should add to that. Should be OK.

Next up was to polish the lenses. Sanded with soapy water and 2500 then 5000-grit. Buffed with the recommended compound and a loose buffing wheel. I have done this only once before, but my memory from that is that it’s NOT like buffing stainless, where a little heat helps. I burned spot in a lens back then. These turned out quite nicely, although 1 backing lens has some cloudiness in it still.

Next, for the frames. I knocked the pitting craters off with a needle file and started polishing with the loose-flap wheel and standard rouge. I noticed it was getting some scratches in it, and then I realized I’d done SS and aluminum, but never chrome. So I switched to some 0000 steel wool with dish soap and that worked well enough. It was probably faster, too.

With that truly minimal effort on the lenses and frames, they look 100x times better. Scrutiny shows they are far from perfect, but a casual glance is a knockout, they seem to almost glow with magnificence.

Faded lens vs polished.

Preliminary results:
The light does not fill the lens like I’d want, and you can see them in there. But OTOH they’ll work, they’ll be done (finally) and I won’t ever see them lit up unless I make special circumstances to do so. I generally don’t see the back lights of this car unless it’s in a parking lot. I’ll surely see the backing lites whenever I back in the garage, though, and that was a big goal of this whole ordeal. Yes, I could’ve just used LED 1157s, but the reviews on them (when I started buying some of this stuff) were pretty sketchy and they would require better reflectivity in the housings.. Plus, I wanted to do something creative.

Next is the harness. No earth-shattering technology here, just new wire, some woven-plastic loom, SS clamps/screws, and a relay for running the backing lights. The backing lights are 100w total, so theoretically 8.3 amps @ 12 volts. I have a tilt column, so it has the reverse lights coming out of that column-mounted slide-switch, and I don’t want to harm that - ~8 amps might be pressing the luck. Plus I have relays on-hand and I like using them, so the backing lights will be fed by a relay triggered from the +12 out of the steering-column switch. So I’ll run a new lead from an inline fuse at the battery back to the relay. I ordinarily dislike such 1-off add-on fuse circuits, but for this purpose in this car it will meet the need.

 

[fury fan]

At this point, everything above was typed while the project was ongoing, so I’m more verbose. The lights are now done (aside from a temporary routing of the main power wire from the kickpanel area, thru the hood hinge, and quickie-hooked to teh battery.

While I was at it, I added an LED trunk lite too. Installation was fairly straightforward, a few hurdles but nothing significant. Was perhaps a 45 min job total. Light has a built-in switch.

Quickie wiring to a power supply to see how effective it is. This is with all the garage lights off. Quite acceptable, and you don’t see the light unless you look for it.

Ran the wire thru the trunklid, down the hinge, and over to the relay area. In hindsight, I wish I’d routed the wire further on the hinge, and fastened it around the curve of the trunk driprail. Oh, well, it’s done now. Can’t let perfect get in the way of good.

Small shot of the harness, clamps, etc. Nothing noteworthy, except that a harness always looks more clean and professional in the imagination, and less-so after all the branches and zipties are on it.

 

[fury fan]

Final results (well, almost). Need to buff and install some trim and try to adjust the gascap cover so it aligns better.

Closeup of the polished lens and trim. They look more impressive in person, in spite of some mild flaws and cracks. Not being 60-years-faded makes them really stand out.

Brake lights:

And the target of the whole exercise:

 

[fury fan]

Summary:

To throw a rough estimate at it, I’ve got $100 bucks in this for the 2 oval lights, the 2 LED chips, heatsinks, a 4-pack of white reflectors, SS clamps, and borrowing some loom away from another project.
The polishing compound, sisal/cotton wheels, weatherstripping, aluminum scraps, and the wire, relay and crimp connectors were all on-hand.

Regrets - I spent a BUNCH of time on this, more than I’d care to tally. There were lots of iterations of the CNC’d stuff, getting things to fit the way I wanted.

Concern - If any of these lights go out, it’s an ordeal to R&R. The whole housing must be removed, which requires removing 3 pieces of trim also, then the chrome trim on the lights must come off, remove the lenses, all to swap out the light. Being LED, they should last a long time, though.

Unsurety - you can see the oval LED and its black bezel. I think only a car-savvy person would recognize it’s an oval truck/trailer light, and only a 65-66 Chrysler person would notice how the lens is not filled with light. I wish it looked different, but as they say in the military – FIDO!

Happy - the backing lites are awesome, exactly what I was targeting. I don’t drive this car at night, but backing it in the garage at dusk will be much easier now.

And overall, it took me back to the days when I liked to modify stuff. And actually did it, instead of just thinking about it...

 

[fury fan]

(in case I need to add anything)

 

[300rag]

@fury fan Yes, it was me. The main difference is that I had the clear lenses...

 

[fury fan]

@300rag
Yeah, that reminds me more fully, that yours were epoxied in place or something.

In spite of all the hassles this gave me, earlier tonight I was eyeballing a set of 68 Newport lenses/housings I have, thinking about what it would take to convert them. And I don't even own a car for them.

 

[Philip Andrews]

Very nice conversion.

I found some modestly good LED retrofit bulbs that use a COB led around the periphery of the lamp, and 3 chips behind something of a lens.
I scuffed the lens to diffuse the light somewhat (which isn't too bad because it shines directly at a reflector in the original lens).
In testing, red LED bulbs offer a deep crimson light.
White LEDs tend to find any impurity in the red lens and turn the light pink.
I had best results with amber color bulbs intended for turn signals.

You may get some good results by fitting a translucent piece of plastic on one of the next reflector "rib" pieces out. That would hide the fitting the way you did the back up lamp (that looks really smart!)

Phil

 

[fury fan]

I did look at some long/slender red reflectors to install, to mount them with standoffs or something, like I did with the backing lites.
But I was at a 'shoot the engineer, deliver the product' stage.

I also looked for chrome bezels for the lights, but don't know which ones would fit my lights.
Some have different qty of mtg holes, some snap on, so clearly they are not fully standardized.
I've decided, if I ever need to go back inside them, I'll just mask the LED lenses and paint the mounting flange silver to match.

 

[Boyd]

I am afraid I lost you on the wiring of the taillights, brake lights and turn signals. Did you use the existing wiring? I didn't follow with the wiring. Can you give us some more detail?

 

[Boyd]

I have been having problems with the light sockets and bulb replacements. Went to LED's and was told that I have to get a electronic flasher unit, but not sure my 65 has a flasher system. Did the truck/trailer leds just wire in? Sorry to be a pain.

 

[Boyd]

Anxious to find out what lights you found. Went to Advanced, Tractor Supply and NAPA and they did not have what looked like yours.

 

[fury fan]

@Boyd
Sorry, I missed your questions until now. Don't know how that happened, I'm usually diligent to answer questions of me.

I am afraid I lost you on the wiring of the taillights, brake lights and turn signals. Did you use the existing wiring? I didn't follow with the wiring. Can you give us some more detail?

I used the existing wiring back to the C-pillar/rear wheelwell area, then spliced new wiring into that. The original wiring exited the trunk, ran behind the bumper, and re-entered the car. It kept the wiring harness out of the trunk but exposed it to weather. Was much easier to just run it in the trunk. It can be seen in pics above, although pics not highly focused on the harness itself.

Harness was made out of individual primary wires, split-spliced as needed to go to qty 2 of each light, then covered in woven loom.
It would've been cleaner to have a harness to each set of lights, but that makes for a fat harness.
Backing lights run thru a relay triggered by the original backing light circuit. I'm a big fan of relays to reduce load on old wiring.
Solder and liquid electrical tape make it all forever-good, and it's inside the trunk and protected from the weather anyway.

I have been having problems with the light sockets and bulb replacements. Went to LED's and was told that I have to get a electronic flasher unit, but not sure my 65 has a flasher system. Did the truck/trailer leds just wire in? Sorry to be a pain.

You car will have a flasher as part of the turn signal system.
You will need an electronic flasher if the LEDs flash too quickly. Our original thermal flasher uses the electrical current to heat a bi-metallic strip that bends when it gets hot, and breaks contact. It cools, and makes contact again. It's 'tuned' to the qty of incandescent bulbs most cars have.

So with LEDs, the current is a lot lower, so it heats the bi-metallic strip just a little bit, so it doesn't bend very far. It then cools quickly and makes contact again quickly. Making LEDs flash too fast.
I still have standard bulbs up front in the turn signals, so the total current is high enough, my flasher works a little faster but it looks OK.
If I ever put LEDs up front, I'll put an electronic flasher in.

The truck lights will have 3 wires - marker/taillight, the brighter stop/turn, and a ground.
Our original lights generally ground thru the metal socket, so you'll need to add a ground, either to a nearby screw, or a dedicated length of wire (which is what I did).

Anxious to find out what lights you found. Went to Advanced, Tractor Supply and NAPA and they did not have what looked like yours.

The oval S/T/T lights I used are industry-common in the truck/trailer market.
It's just a flange-mount oval light, lots of companies make them.
They will vary by lens color and wiring attachments (blunt cut or with a connector), and flange-mount vs grommet mount, but otherwise they are standard.

 

[Mike66Chryslers]

Excellent work, they all look great, especially the backup lights. I retrofitted the same style of license plate light onto my Chryslers as you did. I love what you did with the trunk light. I'm sure it works much better than the factory bulb over in the corner of the trunk. Where did you find that one? I was thinking of using stick-on white "LED tape", but I may steal your idea instead.

 

[fury fan]

It snaps into 2 screw-on clips, which I like. Although it requires more accuracy in drilling the mtg holes than a screw-thru-housing design.
It was pretty easy to mount except it needed 2 spacer blocks due to the curvature of the inner trunk lid where I mounted it, to get the clips out of the curvature - the light bridges the curvature.
I mounted it above the latch mechanism, where it's really not noticeable.
If mounting somewhere else, no big deal. Different trunklid might be easier, too.

Good price, and lots of lumens for the task. Makes it like daylight in there. (see the pic in with the green box in the trunk, that is the LED light at nighttime, with no garage lights on)

Amazon product ASIN B09N34GJ1S

 

[Boyd]

Just installed 6 inch oval LED's and where one of the installers said his LEDS had a white ground, my LEDs the black was the ground. The lights did not come with a sematic or directions and came from China. That is not a problem but it did cost me some time. I would bench check your lights before you get excited like me and start the install.

 

[MoPar~Man]

I must have missed this thread when it was first posted. Was it your intent to use such a high-wattage LED for the backup light? I would have used a lower wattage LED, and it wouldn't have required a heat sink because I wouldn't think the reverse gear is used too often.

 

[fury fan]

I must have missed this thread when it was first posted. Was it your intent to use such a high-wattage LED for the backup light? I would have used a lower wattage LED, and it wouldn't have required a heat sink because I wouldn't think the reverse gear is used too often.

I originally planned to use 4 smaller 10-watt LED chips, but the 50-watt was much cleaner to install. Fewer screws and much less wiring to route to the chips (even less than 2 10-watt chips).
I don't know that mine required a heatsink, because as you mentioned, reverse lights aren't on for that much time.
But I put them on because the sinks were cheap, and the project had already suffered significant scope-creep.
Plus this car must be backed into a non-lighted garage, it's a tight fit, and sometimes takes 2 or 3 attempts to get it in the correct location.
Wanted to make sure no disappointments (and I have none).

If/when I do it again, the size of the reverse lens will likely determine what I do. 65 Chrysler has a pretty big lens and housing for this. 68 Fury is really small.