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MG TD TF 1500 - Panel ground

This topic has be addressed many times according to the archives but I can't get a clear idea of what is correct. I am installing a new wiring harness in a 52TD. I think I have everything worked out except the ground from the main harness (black wire from terminal E on the 5 post control box). None of the wiring diagrams I can find give a clue as to where it should attach. When I disassembled my car it was attached to the top center panel bolt (non-original harness with all the wrong wire colors). I have seen others attached there as well. But I have also seen pictures of this wire attached directly to one of the horn push mounting bolts. The WSM diagram shows the horn push grounded and it seems this would be a good place for the ground. The horn circuit would ground directly rather than through the panel.
But which is "correct"? How was it done originally?
B Mooney

Any one of the mounting screws for the center panel works fine to attach the ground wire. Cheers - Dave
DW DuBois

This is where mine was attached. See pic. The black (earth/ground) wire was secured to the ammeter U clamp which bears against the centre panel ensuring it is at earth potential. When I replaced the harness I refitted it in the same place. Can't say if it was original though, but it does seem a logical & secure place to ensure a good ground. Cheers
Peter TD 5801

P Hehir

I think originally was through panel mounting bolt. The ammeter was originally held in by bent metal tabs and did not have a bracket/thumbscrew mounting (this was common fix/conversion when tabs broke off). Wherever it is placed, make sure not paint/corrosion, etc. on panel/bolt heads, etc. George
George Butz

Attached is a Dave Braun picture of the back of his dash before restoration.
I used it as a model for mine.
I have inserted a red arrow where I found the ground.
Although not visible there is a large flat washer under the ground and nut.

I used this point as a common ground stud and added additional ground wires.
Mine is shown in the next picture.

Jim B.

JA Benjamin

Back of my dash.
Ground terminal on top.
Multiple lugs.

I hope it was ok to post the picture.

Jim B.

JA Benjamin

This a good spot for the gages, BUT still need a ground wire to the frame. I ran a ground to one of the bulk head bolt.
M Grogan

I believe, if I remember correctly, there is a ground wire in my harness.
Its grounded on a bolt on the firewall as MGrogan, notes and then to an additional wire, under the same lug.
I used bullet connectors and joiners to connect the dash to the harness wires.

In the picture, there is a serrated lock washer under the lug to insure ground.

Jim B.

JA Benjamin

My harness has a ground wire as well. Cheers
Peter TD 5801
P Hehir

Thanks for all the input. I ended up attaching the black ground wire from the main harness to the upper center panel bolt. Continuity checked out ok.
B Mooney

This thread was discussed between 01/08/2016 and 02/08/2016

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