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MG Midget and Sprite Technical - Relay for main beam and spotlights

Hi, as part of my rewire I am thinking of installing relays to my head lamps. They are standard but I might upgrade them to halogen in the future.

For the time being I will be putting my spots on a relay wired to a seperate switch.

In future if I wanted to wire my spots so that they came on with my main beam would I be able to link them into the same relay and if so what rating would it need to be?

My electrical knowledge is limited so go easy on me!!!!

Thanks
Mark
Mark Whitmore

Mark,
it will be best if you leave the spots on the relay and then wire the relay coil in to the high beam circuit when you add the relay for them.
I know it sounds strange but this way you can make both relays "average" size and if one goes off you will still have half the lights.
Drop me a PM if you need a wiring diagram.

best of.....
MGmike
M McAndrew

In theory a relay can do 30 amps/ Two lights with 55 watt bulbs will be circa 10 amps and the relay will lost for ever.

Ay 20amps you have connection problems, possible heat problems and probably last say two winters. I have had the problem running two 100 watt bulbs.

So follow Mark's advice.

eddie

Eddie Cairns

I fitted 3 relays.
One for diped beam, one for main beam and one for spots.
The spots go with the main beam.

It are 3 30 amp fused relays, mounted on the inner wing where the connections to the front loom are.

I use the original wiring from the switch to the relay.
Low beam wire goes to the coil on the relay and then to ground.
Main beam wire gets split in to 2 to fead both main and spot relay coils which then both go to ground.
Power comes from a thick gauge wire from the start realy then split in 3 to fead each relay
And from the relays power side main and low beam are then fed through the original wires and for the spots I layed new wires.

And it is a lot brighter even with the normal bulbs.
With the halogens it is realy good
Onno K

I fed mine from starter relay to a separate fuse box and 3 relays just for the head lights and spots don't know if they required fuses but years of electrical training would not let me do them without.
mark (1977 1500 Midget) Preston Lancs

Main reason I had for fitting relays was to make the dip switch contacts in the steering column stalk last longer! Aftermarket switches not as good as the originals and do tend to burn out pretty quickly when handling full headlight current.
Guy W

Has anyone fitted the Moss headlamp relay kit ?

The numerous relays on e bay is a bit confusing (well to me !)- so a kit would be simpler or can someone specify a make type that is suitable ?

R.
richard boobier

Thanks for the advice, will be going down the 3 relay route as it's tried and tested!!!!

One more question though:

If I got the relays with the blade fuses fitted, is that the same as fitting an in line fuse?

Thanks
Mark
Mark Whitmore

I'm not aware of the Moss kit, but there's a guy called Andy Capy that advertises in Enjoying MG.

I can't vouch for how good it is, but it's here on his site...

http://homepage.ntlworld.com/tim.fixit/capy/Accessories/

I will probably do my own, as I prefer the wiring to be the right colours.

Edit: Just looked at the Moss kit. At £76 I'll definitely be doing my own!
Dave O'Neill2

Dave,

The kit I noticed was only 2 relays (not the 4 in the expensive one) 117515 @ £35.
Why would you need 4 relays ?

R.
richard boobier

Mark, yes the fuse is the same as an inline and will connected in the "load" circuit e.g. between the main supply and the lights. The coil will be fused by original light circuit.

MGmike
M McAndrew

<<The coil will be fused by original light circuit.>>

Except that the original light circuit isn't fused.
Dave O'Neill2

Autosparks 30A relays are only £3.51

http://www.autosparks.co.uk/product_info.php?products_id=1066
Dave O'Neill2

found this when i did mine

http://www.rowand.net/Shop/Tech/WiringHeadlightRelays.htm

and bought some bits from here

http://www.polevolt.co.uk
mark (1977 1500 Midget) Preston Lancs

Dave, thanks for the correction, I forgot the lights are on the live side.. In line fuse on order ;0)

MGmike
M McAndrew

I bought correct colour wiring from here:

http://www.vehicle-wiring-products.eu/VWP-onlinestore/cable/thinwall.php

also 5 blade relays R20BC
http://www.vehicle-wiring-products.eu/VWP-onlinestore/relays/relays.php

terminals 87 and 87a for power to the bulbs each side.

I tool power form the original wiring to 85 (switch live), and used new wiring for earths and live to the bulbs. Ran new fused live power feed and earth all the way back to the battery.

Hugh Alison

I found this article quite useful for the wiring explanation

http://www.danielsternlighting.com/tech/relays/relays.html

alistair
A Gilchrist

Hi all, thanks for all the advice.

I was debating wheteher to have the spots on a seperate switch but I think I will have them come on with the main beam.

Could you let me know if the attached rough wiring diagram would be ok to use (sorry for not numbering the terminals). I am looking to use the main beam relay output to activate the spot lamp relay.

All 'solenoid' wires are fused through a late midget fuse box and all relays are fused (not shown on pic).

Also my new loom doesn't have the provision to flash the headlights but my stalk does. I guess I will have a wire or two free.

Could the unused wires be used to add a second switch to the main beam relay or am I being silly?

Would it be ok to use 3mm wire from the solenoid and branch off (also with 3mm) close to the fusebox? The VWP website says that this wire will handle 33a.

http://www.vehicle-wiring-products.eu/VWP-onlinestore/cable/thinwall.php

Standard sealed beam lights (may upgrade to halogen 65w/55w) and 5.5" wipac spots with (i think)55w H3 bulbs.

Would 2mm be ok for the rest of the additional wiring?

Appologies if this is simple stuff but electrics are not my strong point and I want to have it all ok in my head before I venture into the unknown!!!!

Thanks
Mark


Mark Whitmore

Hi Mark, I took my spot lamp relay trigger from the main beam wire from the switch side rather than the lamp side. Also took the ground for the spot lights back to a switch under the dash so I could either have them on with the main beam or off.
While I was cutting into the loom on the inner wing area I relayed the electric fan and horns too.
A nice line of five fused relays bought from Halfords for a £1 each (old stock) cleared out IOW, Soton and Eastleigh stores!
Also fitted some diode fuses which glow when blown, I thought a good idea if a fuse blows after dark!

Regards, Tony
Tony G

it might just be me but if you have additional lights that work with main beam they're great for lighting the county up but on a straight road you have to dip to save the the car coming the other way being blinded when it's a long way from you, you then go from loads of light to what now seems like a very dim dipped light that needs a a white stick to find the verge

there are rules about where the lights can be fitted, their aim and when they can operate but I can't remember what they are, I do remember that the rules are different for a single spot light and they may differ depending on the age of the car

I've just got H4 halogen headlights and they are better than the (newish) sealed beams I had before and are good enough for my use but I would want more if I lived in the countryside
Nigel Atkins

I did mine almost exactly as Onno described. And, I also prefer the main and spots wired together so if I encounter an oncoming car, I can switch both off quickly without having to fumble around looking for another switch. I also spliced into the wiring harness on the inner wing and used the existing wires to go from the relays to the headlights, which are sealed beam halogens - don't know if that is what you use over there. But, I'm thinking of upgrading to something like a Hella replacement unit with H4 bulbs, and maybe higher wattage bulbs. Will the stock wires handle it or should I rewire from the relays to the bulbs with heavier wire? Anybody use higher wattage bulbs for the street (I think our standard is 55/60)?
Thanks,
Jack
Jack Orkin

The problem with 100watt bulbs is that the headlamp connectors are getting old and are made of spring steel that is not as springy anymore.So a looser connection.

The tendency is to get overheating at the connector that is deigned for 5 amps and is having 10 amps through it in a poor state. Therefore it is important that the connectors and the earths are top notch.

Further no chance of main beams and spots of one relay.

eddie
Eddie Cairns

that's not the only problem with 100w bulbs
Nigel Atkins

They are also not e marked so of dubious legality and the quality control of the beam pattern is not very good as they are used of road.
Eddie Cairns

Nigel there used to be rules about driving light placement some years ago.

The only rule now assuming two lights is that they are not nearer the outside of the car than the dipped lights.

No height rules min or max any more and no minimum distance between centers or inner edges.

Fog lights have different rules as they do not go out with the main beams as a driving light has to do.

The regs are gere

http://www.legislation.gov.uk/uksi/1989/1796/made
Eddie Cairns

Thanks Eddie, my 1970 AA Book of the Car is getting a bit outdated with current legislation
Nigel Atkins

I fitted Wipac Crystal clear plastic headlamp units

http://www.paddockspares.com/pm678-wipac-crystal-halogen-headlamp-conversion-kit-pair-left-hand-dip-uk-and-australia.html

plus Osram nightbreaker Plus extra-bright bulbs

http://www.osram.com/osram_com/products/lamps/automotive-lamps/automotive-cars/halogen-light/night-breaker-plus/index.jsp



Very pleased - as good as modern car lights, no need for spotlights.
Hugh Alison

I thought about similar bulbs (when they were half price) but what does the lifespan 150 h or 300 h mean?
Nigel Atkins

Unless it is a daily runner and used all winter it is unlikely it will run up 150 hours of headlight use anytime soon.

If a daily runner for an hour each way a day say 150 to 200 hours a year.

eddie
Eddie Cairns

Hi, thanks again for all the info.

I will be sticking with my sealed beams for now and will put it on my list as a future job.

The main and dipped lights will have relays and I like the look of the spots on the car and it seems a waste to have them fitted and not wired up.

Thanks
Mark
Mark Whitmore

Thanks Eddie, so it is hours

I wonder how many hours the standard H4 bulbs last, I can't ever remember changing one

I've never thought about how many hours I use the headlights but I'd have to factor in daytime use in poor weather or light, longer night journeys to/from and during holidays and tours as well as usual use but I suppose it it's as much as I first thought
Nigel Atkins

the Osram bulbs are fairly expensive - but I'm running with a very small Kubota 40A alternator (K-series mounted fairly far forward without cutting the battery tray).

I didn't want spots because of the extra load on the alternator - or higher wattage bulbs for the same reason - and because I didn't want anything that would reduce the airflow. The bulbs make such a big difference, I put them in the Rangerover as well. Need good wiring to get the best result.

If they last a year or two I'll be happy.
Hugh Alison

Mark

I'm in the process of doing this, though at the moment I'm not doing spots.

I've got a new 2 position switch in the dash for the lights with the first position for side lights.

http://i72.photobucket.com/albums/i178/lloydiemac/IMG_0042.jpg

I haven't worked out how to retain sidelight only operation with relays bearing in mind the idea is to avoid running power through the switch, without putting them on a relay too?

I'd hardly use just sidelights, but it'd bug me to have switch that doesn't do something on one click and sidelights that can't work.

Or am I missing something?

Lloyd
L McInally

Lloyd
Just run the side lights through the switch.
Their wattage is so low it does not strain it
Onno K

Hi Lloyd, as Onno says, just leave the side lights wired as they are.
The dipped beam wiring that runs through the switch is only there to activate the relay the side lights can operate as they always have.

Loving the dash with the extra gauges!!

Thanks
Mark
Mark Whitmore

Cheers Mark.

Took a bit of work and a scrap old dash to cannibalise but it works very well and is properly done - no pop rivets etc.

There's a thread on it somewhere in the K-forum.

Lloyd
L McInally

I fitted Cibie H4 headlights last year and am running 100w bulbs, illegal I know but who is going to know any different? They are run through relays and I've been keeping my eye on the wiring particularly after a long night run and all seems OK.
The difference compared to the old sealed beam units is literally night and day and I do love in the country with lots of roadkill potential and I can now drive at a decent speed in the dark without the fear of not seeing what's in the road 50 yards ahead!
Matt1275Bucks


Matt.

You love in the country. That's too much information!

And with all the lights on.
Gavin Rowles

Well I do need to see where I'm ploughing my furrow!
Matt1275Bucks

When you say the 80/100W bulbs are illegal, what age is your car? Unless regs have changed recently, any car older than me, Oct '83, can run them perfectly fine. My mini used to run them, as well as two 100W driving lamps, and a 130W spot light. Despite blinding a copper once as he checked my car over (it was more than a little loud), he didn't say a word other than " well those work...."

PS, all this did need an upgrade to a 70A alternator though as with it all on it was 530W of light.......
S Overy

This thread was discussed between 17/11/2012 and 01/12/2012

MG Midget and Sprite Technical index

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