Problems with the main beam

[gardener]

In my TR6 the left beam is brighter than the right, Is this a lack of negative connection? What I can do?

 

[71MKIV]

Start by going over each connection in turn. Start at the common point in the front and work your way out to the lamp, and from the lamp to the ground point. You are converting electrons into heat somewhere other than the filament of the lamp. The ground point is the obvious culprit.

 

[RonMacPherson]

Do you have a voltmeter? IF so check the voltage at the back of the lights on the connections. Should be equal amounts of voltage to each power terminal, which will change when high or low beam is selected. There should be under 1 volt(I'm being liberal as far as old wiring goes, ideally there should be no voltage) on the ground terminal.. If there is voltage there that means the voltage is not going to ground.

Assuming you have good voltage to the power connectors. Take a jumper lead and hook it to the ground wire at the three prong plug and hook the other end to a good ground. That will help isolate concern. Then just follow the ground. If I remember right they used a push on spade terminal for ground around the radiator grille opening.. May need to update/supplement with a good chassis ground(see Tinster on this, he has put in what appears to be a good grounding bar).

 

[tdskip]

Forgive the question, but are the headlights the same?

Some times it is the simple stuff.

 

[Tinster]

Gardener-

I had a similar problem a few weeks ago -
No low beam on one headlamp. Wires all good
so I swapped over the headlamps. Still no low
beam in one.

I bought a new headlamp and solved the problem.

Swap the lamps and see what you get. If you still
have a dim lamp, my guess is you need a better grounding
wire. I ground wired every lamp bulb in my car with grounding blocks.

d

 

[gardener]

the headlights are the same,so have to be the ground cables.Also here ares ome of my friends that are changing their alternator for the chevy Cobalt alternator.It give more power, as we put A/C and take out the heater system.

 

[TR3driver]

As I think Skip is alluding to; tungsten headlights grow dimmer with use and sometimes can become very dim without burning out. A new bulb may be all that you need.

I believe on most TR6, you can check the ground by turning on the low beams and pulling the lever to the "flash to pass" position. This should turn on both low and main filaments ... if the ground is bad, the lamp will go out.

 

[gardener]

I checked the "flash to pass" and are perfect, lamp keep working.

 

[TR3driver]

So, time to check the voltage at the bulb, with it connected and operating. If the voltage at your dim bulb is lower, you know it's an electrical problem and can work backwards from there. If the voltage is the same (as it should be), then the bulb itself is bad.

Likely you know this, but to access the bulb terminals, you pop off the trim ring, and then undo the three tiny screws that anchor the retaining ring around the bulb. You should be able to carefully let the bulb hang on the wires while you do the check.

 

[gardener]

Thank, Randall

 

[poolboy]

That trim ring that Randall mentioned is expensive to replace. The springy clip can be hard to get hooked when you replace the rim. If it's rusty, it may break. It's also not the easiest to unhook either.
And if the rim is not put back on just right you'll lose it on a bump in the road.

 

[DNK]

That trim ring that Randall mentioned is expensive to replace. The springy clip can be hard to get hooked when you replace the rim. If it's rusty, it may break. It's also not the easiest to unhook either.
And if the rim is not put back on just right you'll lose it on a bump in the road.

That sucker is such a pain to deal with it is easier to replace the light from the glovebox

 

[DougF]

If you go through and clean all the connections in the circuit, apply dialectric grease to the bullets before shoving back into the connectors. It helps slow corrosion caused by the salt air.

 

[TR3driver]

The springy clip can be hard to get hooked when you replace the rim.

What I do on the '3 is stick a flat piece of metal in between the trim ring and the retaining ring, to push the tab through it's clips. My tabs are so old and weak that they simply bend otherwise. You may need to pry gently nearby, to open the gap enough to see inside; but I generally work by feel and the rivet head where the tab is attached to the chrome.

Then tug on the trim ring to be sure it's seated properly.

If the bulb is bad, this might be a good time to consider an H4 upgrade.
https://www.danielsternlighting.com/products/products.html
https://www.britishpacific.com/BPSite/landroverparts/IPF_lighting.html

Although a wiring upgrade will certainly help as well, the stock wiring is entirely adequate to handle the 65/55 watt H4 bulbs; and the improvement over standard (in the US) tungsten bulbs is considerable.

 

[TR3driver]

Hmm, I wonder how hard it would be to convert a TR6 to the TR2 type trim rings? They look pretty much the same, but the TR2 used a screw to retain the ring, instead of a clip.

And the TR6 trims are certainly cheaper than the 3A trims @ $50 each.