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Under the hood grounding point

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wkilleffer

wkilleffer

Jedi Knight
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Hello,

While attempting to cure a lighting problem on my 1974 MGB, I found a grounding point under the hood close to the fuse box. It has two wires leading into it, and one is thicker than the other. It looked like it could be the source of a bad ground, so I relocated it to another screw closeby after cleaning the area to bare metal.

Does anyone know which circuits are grounding there? The reason I'm asking is because my headlights have quit working. All the other lights come on when I flip the switch. I tried jumping the headlight wire to the brown wire at the switch, and nothing happened.

The strange thing is that after moving those ground wires, my right turnsignal doesn't flash.

Headlight trouble seems to dog me no matter what I do, and it's almost as though my memory of how it was cured last time flies out the window.

Are the MGB wiring diagrams that were in the true wiring colors still up on the web somewhere?

Any advice and suggestions would be appreciated.
 
Do the headlights "flash" when you pull the stalk back? If the other lights all work, I'd suspect the dimmer switch itself, the high/low control. Have you a footwell one or is all your lighting control on the column?
 
Sprite and Midget ones are on the web but Bs???

I know there is one in the back of your manual, either one.
 
[ QUOTE ]
Do the headlights "flash" when you pull the stalk back? If the other lights all work, I'd suspect the dimmer switch itself, the high/low control. Have you a footwell one or is all your lighting control on the column?

[/ QUOTE ]

Yes, the high beams flash on when I pull the stalk toward me. Nothing happens when I push it forward. The control is on the stalk with the turnsignal switch. The switch might be original to the car. I took it off yesterday to see how it worked, and the contacts all look pretty worn.
 
[ QUOTE ]
Sprite and Midget ones are on the web but Bs???

I know there is one in the back of your manual, either one.

[/ QUOTE ]

What I'm talking about is where someone broke the factory diagram down by each system, and made the wires the correct color, rather than just a black line. You could look at a diagram for just the lights, or just the ignition system, dashboard instruments, etc. without having to worry about getting lost in an unrelated area. I have the Haynes and Bentley manuals, and they are helpful. But those charts simplified things a bit.
 
Oh, I see them on eBay from time to time like that.
 
Well, they used to be on a website somewhere, and I forgot to bookmark it, of course. Hate to think that it might be gone. It was a great resource.
 
Boy do i love this forum! /ubbthreads/images/graemlins/thumbsup.gif

i am in the middle of the opposite problem (the blue/white low beam wire is hot all the time, looking for the short)
and the colored schematics will definitely help.

I am not sure what is the cause and what is a symptom, but when i put the lights on(headlights, not parking lights) the ignition turns on (dash gauges on, fuel pump starts to run)

Thanks.

William, i am very curious to know how you resolve your issue. I am off to check the aforementioned ground.

Rob
 
and now i just realized that the blue and white wire is the high beam....

i believe my problem is between the headligth switch and the dimmer switch, the blue wire at the dimmer switch is hot when the key is off and the switch is off.

Rob
 
[ QUOTE ]
The wiring diagrams you are looking for are still on the web, at https://www.advanceautowire.com Just click on the "stock Schematics" button on the left.

[/ QUOTE ]

Turns out I had a copy of them saved on my hard drive already /ubbthreads/images/graemlins/tongue.gif

But it's good to know they're still out there.

On the subject of MGB wiring; has anyone bought the MGB circuit book written by Rick Astley? Looks new. It came up while I was searching for MGB wiring stuff.
 
This book is brand-new, and some who pre-ordered are receiving their copies already. Just about everybody with any experience on any forum swears by Rick's expertise, so I'm definitely waiting for my copy to show up in the mail. From what I hear, it's worth every penny.

R.
 
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