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SORN
by OldSkrote - 31/07/25 02:07 PM
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New
by Rex_tulips - 30/07/25 07:59 PM
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Most Online1,046 Aug 24th, 2023
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Joined: Jul 2012
Posts: 1,615 Likes: 1
Talk Morgan Enthusiast
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My 1992 (M16) plus 4 failed the MOT because of no main beam on drivers side head light. New bulb - no good, checked the fuse and this was OK but there is no voltage on the feed in the head light. I am trying to trace the wiring and I suspect a relay somewhere but can only find two, one being the fuel pump and one beside that which I swapped out for a spare on the off chance - no go. Has anyone had this problem or are there any ideas.
John 1992 plus4 connaught green
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Member of the Inner Circle
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Member of the Inner Circle
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On my 1994 car it was an earth problem. Wiring diagram is here http://www.gomog.com/allmorgan/plus4m16wiring.jpg
JohnV6 2022 CX Plus Four 2025 MG ZS EV aka Trigger
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Thanks John, I have already printed off the wiring diagrams from gomog but it shows a dip/main box, could be a relay, but I can't locate. I will just have to track from back of no6 fuse. If it was a short to earth I would have expected the fuse to blow. I don't know just when the weather has got reasonable.
John 1992 plus4 connaught green
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Salty Sea Dog Member of the Inner Circle
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Salty Sea Dog Member of the Inner Circle
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Can't remember whether there was a relay on my '97 T16. May be worth asking Keith at BHM or Tim Ayres at New Elms?
Graham (G4FUJ)
Sold L44FOR 4/4 Giallo Fly '09 Gen2 MINI Cooper ragtop '90 LR 90 SW
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Graham, I can't remember either. I know with the poor earth the fuse didn't blow.
JohnV6 2022 CX Plus Four 2025 MG ZS EV aka Trigger
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John, try the easy way, before you do anything run an earth from the bulb to a screw holding the headlamp bucket. If nothing else it will eliminate a bad earth. Both my lamps have earth flyleads fitted to earth this way, its easier than trying to trace a bad earth in the loom. A short to earth will usually blow a fuse but a bad earth will not, it just won't work.
1993 T16 +4 Lancia Blue.
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And that is what I did when I had the issue
JohnV6 2022 CX Plus Four 2025 MG ZS EV aka Trigger
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Thanks I will try that in the morning but what I can't understand at present is that the dim filament lights and it uses the same earth wire.
John 1992 plus4 connaught green
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Joined: Mar 2013
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Talk Morgan Regular
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Poor earth, I had the same problem also with a side light good luck
Magwa 1950 Allis Chalmers B tractor 2000 Porsche boxster 2014 Skoda yeti 4x4 elegans
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The earth is good. I have found a "black box" under the dash with 8 wires two of which are blue and white, the same colours as appear in the headlights. Continuity checks that the one lead to the good main beam gets voltage whilst the other not. A potted relay I think. Any ideas where to get a replacement.
John 1992 plus4 connaught green
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