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Headlights

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Bob_Bobrowski

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My headlights work only on ther high beams, not the low. I don't believe both bulbs are burned out. Could the problem be with the switch, or should I look else where? Thanks.
 
The light has three connectors on the back of it, if you take it out you can connect it to a battery you can quickly check that both the dim and bright filaments work.
 
The odds are slim that both headlights would fail at the same time aren't that great. But I'd start by just popping one of headlights out and measure the voltage to ground. If no voltage you're going to have to trace the missing voltage back to the headlight switch. There's only a couple of connections where you could loose it.
 
Bret said:
The odds are slim that both headlights would fail at the same time aren't that great.
Click to expand...

Making basic assumptions like that usually makes me spend a lot of time trying to solve a problem that never existed. /bcforum/images/%%GRAEMLIN_URL%%/wink.gif
 
Don't overlook the dimmer switch either, the low beams turn off when the high beams turn on. I had a failure in that that killed the low beams.
 
Simple. Put a voltmeter on the headlamp socket. If you get 12 volts, then the bulb is bad. If you don't get 12 volts, then the problem lies elsewhere.
 
Usually when neither headlight is burning, one has not been burning for awhile. They seldom burn out at the same time, but the probability of both of them being burnt out at the same time are fairly good. The conversation usually starts with "I noticed my low beams getting dimmer."
 
Tullamore said:
Bret said:
The odds are slim that both headlights would fail at the same time aren't that great.
Click to expand...

Making basic assumptions like that usually makes me spend a lot of time trying to solve a problem that never existed. /bcforum/images/%%GRAEMLIN_URL%%/wink.gif
Click to expand...
Why do you think I suggested checking the voltage at the headlights? /bcforum/images/%%GRAEMLIN_URL%%/smirk.gif
 
Have you check your headlight fluid lately? Could need to be changed, and try synthetic it lasts longer.












(sorry, couldn't resist - do what Bret said and check the voltage)
 
I had my low beams go out not too long ago. I would follow everyone's suggestion of checking the voltage at the headlights to rule out the possibility of the lights being blown.

In my case, it turned out that my turn signal/dimmer switch was faulty and failed to complete the circuit for low beams.
 
I tested the both bulbs with a 12v power supply, the high and lows are good on each. I checked for power at the plug with a volt meter, and nothing on the low beam lead(and they weren't low on fluid, either). I'll see if I can get to the dimmer switch.
 
Tested the voltage at the dimmer switch, and the power seems to be leaving the switch ok. Checked it at the first connctor I found under the dash and tested good there. Does anyone know if there is another connector under the dash before it goes out into the engine compartment?
 
If you look at the schematic there's a couple of bullet connectors up in the front of the car linking the headlights together.
 
While you're diagnosing this stuff you might consider (and get other opinions here about it too) getting a good size tube of dialectric grease to seal the connectors up with. I had several that were acting up now and then so I just pulled them apart, cleaned them, gave them a good going over with the grease, and reassembled - haven't really had a problem in years since. Maybe that's just because I took everything apart, but I don't think it hurt anything either /bcforum/images/%%GRAEMLIN_URL%%/smile.gif
 
aerog said:
Have you check your headlight fluid lately? Could need to be changed, and try synthetic it lasts longer.

(sorry, couldn't resist - do what Bret said and check the voltage)
Click to expand...

Just be sure not to mix incandescent fluid with the halogen stuff....that will really let the smoke out!



(sorry I couldnt resist)


mark
 
And blinker fluid is entirely different! If you mix them up, you could end up with intermittent headlamps. Not that it would be unusual for an MG! /bcforum/images/%%GRAEMLIN_URL%%/wink.gif
 
But brake light fluid is the same as what you put in your master cylinder...you just have to use a syringe to get it in the end of the little bulb.
 
There are a lot of newcomers to the MG world and I think it's really important we get serious about this. I don't want anyone to be misled by this thread, or to go down the wrong track. Contrary to what a lot of people believe, MGs did not use metric hardware. Please, please be sure to use English headlamp fluid. Metric is too fine and will tend to leak out in very short order!
 
tony barnhill said:
But brake light fluid is the same as what you put in your master cylinder...you just have to use a syringe to get it in the end of the little bulb.
Click to expand...

That would be a bulb syringe.
 
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