H-4 Headlight connector, circa 1993

[1Sourdough]

After reading a recent thread about LED headlights I ordered a 3800 Lumen module from Cyclops.  Because of a long standing dissatisfaction with the headlight on the 1993 Strada, I decided to at least install it in that motor's 5 3/4 in headlight to see if it would make a difference.  Although I have had the light out, and have removed the bulb in the past, I was surprised by two things:

The white nylon plug at the end of the headlight harness had a black segment, showing the Ground connector had been quite hot for awhile, and;
The headlight and bulb have only one thin index groove and ridge to orient the bulb in its housing.

The bulb is an H-4, and was made in China.  Must be the European standard?  I am ordering a replacement unit just because I don't want to have to look for a bulb with that (to me, at least) non-standard design. 

I installed a new headlight plug in case the heated connector has lost enough springiness to not be capable of being tightened now.  I have seen that in the past, a female connector which has worked a little loose and gotten hot because of resulting high resistance had lost its tension and when I tried to tighten it a bit, it just crumbled. 

It was a surprise that this was the ground connector.  I had thought at first it would be the high beam, higher current flow connector but after awhile the gray matter pulled up the thought that if current is going into the high beam filament, it's sure enough coming back out through the ground wire! 

While preparing motorcycles for the summer it might be a good idea to check all the push-on connectors for tightness.  The headlight is noticeably brighter for that little bit of work.

I did install the LED unit in the EV, and was stunned how much brighter than the H-4 it is.  Reading about it, even with pictures, does not carry the impact of turning the key and seeing things light up out in front!

[rodekyll]

H4 is a bulb base standard.  If yours looks different, it's not H4.

How big is the ground wire?  the heat you describe is either the wire is too small for the load or the resistance is too high -- probably from the ground connection bad on one or both ends.  You found and fixed the bulb end of the ground.  It might also be a symptom of the other end being dirty/loose.

How long has the Chinese bulb been in there?

[flangeman_70]

H4 is a bulb base standard.  If yours looks different, it's not H4.

Actually RK is incorrect in this instance.
The H4 is the lamp standard not the base. In most modern auto applications we see a H4 with a P43t base, what you need, from what you describe for your Strada, is a H4 with a P45t base.
See attached link just for reference http://onamlight.kr.ec21.com/GC00085328/CA00085949/H4_Type.html

Adam

[rodekyll]

Sorry about that.  I forgot the early, 'big base' bulb existed. 

[1Sourdough]

Well, I worked up a lengthy response to Dave's answer and then managed to scrub it.  Good thing, since I had not read the second and third replies!

The bulb used to go nearly dark when switching between low & high beams, especially at idle or with the engine stopped.  Does not do that now.  The wire is pro'ly the metric equivalent to 14 Ga.  High heat discoloration local to the female wire end terminal at the headlight.  No indication of heat in the insulation or the push-on connector at its other end.  When I finally got around to carefully peering at the three wire ends at the headlight end I notice the hot one has a visibly more open gap than the other two.

When I followed the ink it returned a "Service Unavailable" error.  Where was that P-45 primarily used?  I got my first H4 headlamp in Hope, BC in 1972, and it was the three tab style, I think.  Maybe everyone outside North America used them since the headlamp says Made in Italy, and the bulb is Chinese. 

[HDGoose]

Time for headlight relays.

[1Sourdough]

Time for headlight relays.

I have thought about that... Since it's not hard, there's no particular reason it hasn't been done, I guess.

[redrider]

" that if current is going into the high beam filament, it's sure enough coming back out through the ground wire!"

Eh, not quite. Electrons are neg charge and electron flow is towards the pos. So the juice really does flow uphill. Positive ground makes sense now. The symbol for Current is I; imaginary as my electronics instructor 'splained it to me 40 years ago.

[1Sourdough]

I intended an electronics engineering degree but after an instructor became very passionate in his discussion (monolog, doncha know?) of electron flow vs. hole flow it seemed better to pursue a career as a technician.  Why, I didn't even have to worry about the Left Hand Rule any more!  Or was it Right Hand Rule?  Dunno, I just fixed the stuff for several decades...