I haven`t seen that type of connector. I was thinking of the run of the mill electrical crimp style.

How much and what heat source would you use on these connectors with solder?

I worked for Sylvania back in 68, and did a lot of soldering. they had some Govt contracts. that is where I learned solder is for continuity, not strength.

Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

They told me I can just place a soldering iron up against the center bit with the solder ball in it, though I'm thinking I may end up with heat shrink on my iron. You can also use a flame, like a mini-torch, but I'd be a little worried about collateral damage, heh.

Here's a kind of stupid question: Do you guys think it would be best to patch it in closer to the green terminal in the corner of the headlight, or closer to the plug itself (i.e., right behind the bowl). I was thinking it might be better to do it right behind that green terminal, since the new plug came with plenty of extra wire ... since it would be less hot there and also less likely to be flexed whenever I take the bulb in and out. Maybe I'm overthinking it. Also, the wires on the new plug are a bit thinner than the factory ones ... but maybe it's just the thickness of the coating ... is that something to worry about?

__________________
1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)

Job finally done. I attached the new harness in between the two sheaths on the headlight harness. I tried the special connectors that came with it, but couldn't get the solder to melt right, so I just did a regular solder job, with heat shrink over the joints. Seems to work fine so far, but I'll see over time. I also took the other headlight out to replace a cracked lens, and found on reinstallment it did not work anymore. That one turned out to be corrosion in the 4-pin plug, which I cleaned up using sandpaper rolled into a tiny tube and electric cleaner. What a project this turned into after starting as a simple bulb change. Taking all those little screws in and out and trying to align everything was not fun in the freezing cold. At least I wasn't out in the wind.
Bad news is I found loads of rust behind the passenger headlight, and in the wheel well ... when it's a little warmer, I need to pull the fender, air cleaner and more to really clean that up. I did POR15 a small patch of surface rust on the other side where the W9 ground is.

__________________
1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)

Good job on the old school solder and heat shrink. That should hold up great as long as you got a snug seal on the heat shrink.

Note that the Benz connector pins are silver plated copper. If you sand them, you will strip the plating and the copper will corrode again shortly. If you put some dielectric grease on the pins that should help keep the corrosion at bay. Silver polish (the pink stuff in a jar) or Tarn-x works wonders on these without damaging the plating.

If you have damaged connectors they are rebuildable. Pins and housings are still available.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Is that the case for the female connectors as well? The corroded ones were actually very green inside, so I was thinking they were copper? The pins on the back of the headlight itself still looked good (silver) so I just wiped them with electrical cleaner. Good to know in the future! ... I will be sure not to sand them. I do have several extra female ends that I can solder on if the ones on mine are damaged. In the meantime I will look into dielectric grease ... don't think I have any.

__________________
1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)

If you have female socket pins that are corroded you can get replacements, or I would try a dip of Tarn-x after removing the pin from the housing.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Good work on the fix.
Nothing like a blown or faulty headlight to attract the boys in blue eh?

I had the same problem in my car, melted a female prong. Careful buying new plugs as they need to be slender enough to to pass through the plastic "nut" that butts against the headlight itself. I made this mistake.

My quick fix consisted of sanding the plug surface back to flush, and slathering the bad connection in dielectric grease. Might be worth a try to save some dough. I had to angle my headlight slightly in the plug (I then wrapped it tightly in electrical tape) or the light would go out again after a bumpy ride. No problems so far.

Also I upgraded to Sylvania (Gold I think?) high performance headlights; expensive but i don't regret it.

hey guys,

about a year ago i replaced my headlight assembly wire harness with a junkyard harness , which was in what seemed like good condition. before installing the junkyard harness, i made sure to clean both the bulb pins and the headlight socket(female end) with a quality contact cleaner.

a few weeks ago i noticed that the junkyard/replacement harness has once again melted , so i have ordered 2 brand new 9004 (high temperature) headlight sockets.


1) on another site there is mention that a bad/dirty ground can cause the headlight socket to melt. question for the electrically savvy: is it possible that a bad ground is causing the socket to melt?


2) according to the picture attached below, there should be a ground wire behind each headlight assembly. i've had the headlights off before, but cant recall seeing any ground wires back there. anyone know where they are, where to look?


thanks

Attached Thumbnails

 

Hi folks,
lets analyze the problem on a more scientific basis.
Replacing the Headlight Bulb with a higher load e.g. so called high output bulb, will most certainly increase the flow of current while in operation. Higher current means that there has to be enough room for the electrons to flow freely (well semi free ) from the source (Battery) to the bulb. If there isn't (wire gauge) electrons will hit each other on their way to the bulb and thereby heat up the wiring more. This includes the spade connector and weak points (mostly at the crimp ends).
The heat generated can be significant and as much as to melt the plastic housing.
A simple over thumb rule is a 55 Watt bulb at 13 Volt will cause a current of 4 1/4 Amps to flow to that bulb.
All of the wiring, starting from the source, must be able to handle this amount of current.
Increasing the power to 65 Watt would increase the current to about 5 Amps. I don't think that the Mercedes engineers designed without overhead, so the 16 or 14 gauge wire, in my opinion is fine.
Now if we look at the terminals, there is a spade type connector that only works (as intended) if the flat side completely makes contact with the terminals on the bulb.
In real life that does not happen, or very rarely.
Terminals are cheaply made and after once or twice unplugging the connector the become sloppy, bend out of shape and what not.
With sloppy connections, sloppy meaning mechanically not sound, the vehicle vibration can and will interfere with its connection, too fast for us to see.
Each time it loses the connection, it has a very good chance to arc at the connector. If so, the terminal and surroundings (plastic housing) will get hot and eventually melt the connector.
Remember, an arc gets very hot (Arc Welding as example)

The remedy, or at least an attempt.
There is a di-electrical grease available from CRC (only know the bar code 78254 05105.
The objective is to coat any electrical connection, affected or throughout the wiring, lightly with this grease.

CAUTION: Don't apply overly, there are semi conductive components within this grease. Doesn't cause a short, but could raise other problems, in particular when it comes to computer communication. So watch that there are not grease bridges, only the contact gets the grease.

Also make sure that spade terminals are mechanically in good shape e.g. sit flat and don't have half moon bends, I know it is hard to see inside the housing. Any missing surface, directs the current to the smaller area and causes heat. (More electrons want to go through there)
I think it is best to apply a small amount of the di-electric grease to the spades of the bulbs. The coating does prevent or slows at least down corrosion.
CORROSION:
Corrosion is the build-up of additional resistance at (in our case) the electrical terminals. Too much corrosion will limit the amount of current that flows to the bulbs and thereby dim the output or lumen (candlelights if you wish). If the connection is sound, it would cause some heat built up at the corrosion point. If lose, it will arc at some point.
Above grease will help to prevent corrosion!

Two grounds:
Often, a electrical diagram will show a connection that only electrically exists near the device on the drawing.
In real life the ground may be at the other end of the harness.
Look at the bulbs, there are three terminals. One for the low beam and the other one for the high beam. What about the third one? This is most probable the Ground, since the head light assembly in later models are entirely made from plastic, even the reflector.

I could go on, but refrain from doing so, however hope that it brought a little insight and perhaps even a remedy.

__________________
Mostly, I don't know notin, I just know where to look.
I am looking back, to over 30 years in Electronics Design.
Electrons don't care if they move in a car, computer or relay!

95 W124 E320 M104.992 - Because, I love to repair, naaaah!
Over 221,000 Miles
Cheers,
Norbert