One dim headlight issue

klennop said:

I also don't think the ground is bad because the high beams between the two are the same so if I had a bad ground wouldn't the high beams be dimmer also? Right???

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Same ground for High and low, yes. Try switching the bulb from one side to the other, just to be super sure its not the filament.

Maybe someone put dielectric grease in it?

If the voltage is the same at the terminal then I would think it would be the bulb.

Have someone stand in the front of yer Jeep while you do this....

Hold the lever between low beams and highbeams in the "flash to pass" mode......both filaments (low and highbeam will light)

Ask them to see if the lowbeam filament gets any brighter when you "flash to pass."

Grab an ohm meter and measure the resistance from the ground connector in the socket to the battery. (Disconnect the batt first) A bad ground will show high resistance, and will cause a dim bulb. Also, don't discount the mismatched bulb idea. Just because it's newdoesn't mean it's perfect.

if V= I x R (I=V/R) and the potential difference at the terminal is 12v or thereabouts then shoud that not mean that the resistance isn't too high...or else you would see a greater volatge drop, or rather a smaller potential difference? Though that would be assuming that he measured from the hot terminal and the bulb ground not the hot terminal and the battery terminal or something...

Another place to check for corrosion is Connector 106. It is located on the front left hand side of the engine compartment kind of behind the air box. The right low beam should be violet with a red tracer (pin 13). Fuse 5 in the junction block (fuse box inside) is the right low beam too.

If it were the ground the high beam would be affected too, also, with the (assuming stock) bulbs drawing 55w and 4.58amps on low and 60w and 5 amps at high the high beams would be more likely to melt a compromised wire, or would be more affected. If it were power delivery and ground resistance then both beams would be affected. If it were power delivery and not grounding then you would not get 12~14 volts on the MM using the bulb ground or the negative battery terminal. So that leaves the bulb.....we did say that it measured 12~14v at the connector right...power is power, if its getting there its getting there, right?

I just checked the filament by flashing the pass, it looked to me like the filament got brighter but I think it will be easier to see with the bulb out of the light so I will check that tomorrow.

I also think that dielectric grease was in the socket, however I have heard that too much can reduce current, so now there isn't any in it.

When I measured the power everything was dne through the light terminal, I didn't use the battery for anything.

OK tomorrow I am going to do the following:

• Check to be 100% sure the low filament gets brighter.

• Buy 2 new bulbs and put them in but first I am going to swap the bulbs from one side to the other.

• I am also going to take pictures of the 2 different connectors.

• Measure the resistance to see what that shows

• Check the fuse/connector under the hood. Is pin 13 labeled? I may be able to just follow the wire and figure it out.

Thanks again everyone for the help and ideas. This is just one of those things that I really want to fix. I could let it slide but more light is always better in my mind!

OK Here are some pictures I took with the jeep off. Sorry so many but I want to show everyone what I am seeing.

Passenger Terminal:


Drivers Terminal:


Voltage on Drivers Terminal using both the right and left sides.(LOW BEAMS-Multiple Pics)



Voltage on Passenger Terminal using both the right and left sides.(LOW BEAMS-Multiple Pics)



Voltage on Drivers Terminal using both the right and left sides.(HIGH BEAMS-Multiple Pics)



Voltage on Passenger Terminal using both the right and left sides.(HIGH BEAMS-Multiple Pics)



Now one thing I did notice is that the filament on the low beams compared to the 2 looked different. The filament twords the front is on both lights when low beams are on. However the filament twords the rear also lights up a little on the dim (passenger side). I swapped bulbs side to side and also bought new ones. Same outcome. Brights between the 2 sides looked the same no different. You might be able to see what I mean in these pics.

Passenger Side


Drivers Side:


Then I checked for resistance using the battery and the ground from the light connector. Nothing at all, no resistance.

As I was doing all these tests I did find this, but if I am getting the correct amount of power then it shouldn't matter, unless the wires are backwards or something??


I AM TOTALLY STUMPED HERE!!! Everything points to the bulbs but it isn't??????

What's the driver's side look like?

I don't know what to tell you though. That looks pretty normal right there.

OK after looking at my pictures that I posted. Notice in the pictures when the high beams are on. The multimeter probes are in opposite sides of the terminals to get the same readings from both lights.

Could that be it? The negative wires are reversed on the passenger side from whoever added that extra wire.

it would seem as though that's the problem-- use the violet wire on the drivers side as referance and put it in the same place on the passenger side.
-- look for continuity to groung on the drivers side and note the location of the ground.
-- look for continuity to ground in the old wires and run that to the same location in the plug as on the drivers side
-- by default, you will have the last wire in the last hole.

both plugs should have the same readings in the same holes and voila- brightey-lightey!!!
hope it works out as easy to do as to say!!!!

--Shorty

That was it!!!!!! I just got done switching the wires around and now I have even light!!!! I can't believe that it didn't bother the previous owner, unless they just couldn't figure it out.

Thanks again everyone!!!:woohoo:

I'd definately solder those connections if possible.

And here I am more than a decade after you, hoping to find answers in these posts. Alas, all I found was PhotoBucket's default image. Waste of time....:soapbox:

Main takeaway is that both side should be wired the same (original poster's vehicle had been "modified" by a previous owner and they'd mixed up the high beam and low beam wires in the passenger side connector while adding some other wire for something).