MG T-ABC

Here is the Horn button on the dashboard of MGTC 0820. It has been there since importation in 1976, and have seen buttons identical to this on other MGTCs. Note that it has a large button, letters for "D" and "H" and there is no bulge below the switch.
The next photo of a Horn button seen on other MGTCs shows a smaller button, no letters for "D" and "H" and there is a bulge below the switch.
Is there any consensus opinion about the appropriateness for placement of either Horn button at which serial interval?

Octagonally yours, BOXLEY (Robert and MGTC 0820)

You may know this already but the 'D' stands for 'dip' and the
'H' stands for 'high'. The lever below changes from D to H. But you probably knew this already.

Regards, Joel......

Cars I have had in the workshop that indicated any originality, had the large-button switch. Every time I have seen the small button version, it looked significantly newer.

I have seen the small-button version in old red Lucas boxes, but that may not mean anything, like replacement ignition switches.

Tom Lange
MGT Repair

The small type is incorrect, a replacement item. TC's came originally with the larger one only. I believe later cars like the TD came with the small one. There are a lot of TC's out there with the small one simply because the owner doesn't know the difference.

Considering the rarity and fragility of the original horn button /dip switch I thought it would be sensible to protect it with a relay. A separate fuse to protect the wiring may also be a consideration.

There seems to be a very similar Horn Button & Switch at MOSS with some instructions about connection and placement of wires that lead from it.