Fitting/wiring spotlamps to a 72 MGB

[den9112]

Hi, i am looking at installing a pair of spot lamps to a 72 MGB and looking for a bit of advice regarding the wiring .
My plan is to wire direct from battery with a in line fuse to a relay then feeding out to the spots then earth and getting the switch to work the spots from the high beam so they only come on when i use the high beam...I have seen a few videos and had a look around the net etc and i presumed my set up would be fine but i have seen a few threads mention installing another switch so not sure what way to go...Any help on this would be apreciated plus if i do have to install a switch how would that be wired ...Thanks

[GreenV8S]

The layout you describe seems reasonable to me.

Are you confident you understand electrics well enough to install this yourself?

[den9112]

Off course i am ,but thanks for your comment...
I just was not so sure regarding the legal side ie having to install a switch so it can also be isolated ..

[Panamax]

Your suggested approach is correct. Make sure to put the fuse in a sensible location, i.e. close to the battery and not half way round the circuit!

One point. If you ever want to be able to use the car without the spotlights then you'll need a switch in the trigger wire between your high beam circuit and the relay - not to turn them on but to stop them coming on.

[den9112]

Thanks for the reply ....

[GreenV8S]

den9112 said:

Off course i am

In that case I wonder why you're uncertain about whether you need another switch. The circuit you're describing is quite simple, and it should be obvious how it's going to behave. If that matches the behaviour you want then there's no need to introduce any other complexity.

[den9112]

I do apologise for coming across as being simple ...The circuit you're describing is quite simple..
Sometimes using a dedicated forum for a little bit of advise and encouragement is not to much to ask is it ..

Thanks to another member i got a bit of information that was actually quite useful...but once again thanks for your contribution ...

[GreenV8S]

Panamax said:

If you ever want to be able to use the car without the spotlights then you'll need a switch in the trigger wire between your high beam circuit and the relay - not to turn them on but to stop them coming on.

The original post mentioned having a switch to disable the new spotlights.

[den9112]

I am a ex professional wildlife photographer who as just taken up a new and hobby and that being a classic car that needs a lot of love and attention
...
I have some basic knowledge on cars but learning everyday in my new hobby ,however one of the videos i watched regarding electrics and wiring etc was actually a Australian one which mentioned the legality with fitting spot lamps were they had to have a isolation switch ,i just got a bit confused on this and presumed that it was universal ,i now know differently and i can now wire up without a internal dash switch ...

I notice you have some interest in the TVR well while i was working for a engineering company many many years ago and we made the fuel filler neck pipe for a TVR and one of the fuel tanks they changed the dimensions slightly were the old pipe wouldn't just fit and rather than re tool for it i was asked to see if i could adjust and bend the angles to make it fit which i did ,we also did fuel tanks for british leyland ,sherpa ,lotus ,fodden ,dennis eagle and many more and i did most of the filler necks for them ...

[Panamax]

GreenV8S said:

The original post mentioned having a switch to disable the new spotlights.

It wasn't that specific; it just mentioned "another switch". I was clarifying that this isn't a switch them on, it's a switch to switch them off.

[droopsnoot]

Wire from high beam circuit to fuse, then into switch for spot lights, then from that into the trigger wire on the relay. Separate fused wire of appropriate size from a good power supply into the switched relay circuit, then out to the spot lights. Maybe no need for the fuse on the supply wire, but I'd prefer extra fuses to burning smells.

Apologies if it's already been answered.

[Huzzah]

While you're at it for very little extra effort you could wite the dip and main into delays too.

Less load on original weedy MG wiring and switches plus brighter lights.

[RizzoTheRat]

I did similar on my motorbike, but put a 3 way switch on the signal wire to the relay, with one connected to the dipped lights and one to the main beams. this lets me select if I want the spots to be off, on with dipped (which are permanently on) or on with main beam only.

[Error_404_Username_not_found]

Huzzah said:

While you're at it for very little extra effort you could wite the dip and main into delays too.

Less load on original weedy MG wiring and switches plus brighter lights.

This, all day long.
I have fitted relays (and extra fuses) to my Midget for high beam, low beam, horn and cabin fan, all of which the factory forgot.
They are high power consumers and as standard the full current demand goes through tiny contacts in the stalk switchset, (except for the fan obvs). I had already had to replace a fried stalk switch which are surprisingly rare now. It should live forever with only milliamps going through it.
The headlights went from dingy yellow to clear, bright white from eliminating the voltage drop across the stalk switch, which was another reason to do it as Huzzah says.

[TwinKam]

Back to the MGB, I would 'earth' the fogs relay through a dash on/off switch, rather than 'fire' it with a new live wire travelling the length of the engine bay. The worst that could then happen if it does short through, is that the fog lamps come on.

[ARHarh]

If it was me I would put a switch into the line that feeds the relay from the main beam line, this will then enable you to switch off the spots if needed but also allow them to work with the main beam.

[generationx]

I fitted a couple of sets of auxiliary lights back in the day, the Hella instructions always seemed to work - but now I'd make a more "permanent" wiring connection than the click/splice things included in that kit:

https://images.carid.com/hella/items/pdf/h12273001...

It should be relatively straightforward to include a switch somewhere.

[GreenV8S]

generationx said:

I'd make a more "permanent" wiring connection than the click/splice things included in that kit:

Those Scotch Lock style unsealed insulation displacement connectors are appalling things.

[ARHarh]

GreenV8S said:

generationx said:

I'd make a more "permanent" wiring connection than the click/splice things included in that kit:

Those Scotch Lock style unsealed insulation displacement connectors are appalling things.

Nearly as bad as the original Lucas connectors. The Americans used to refer to Lucas as "the prince of darkness".