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MG MGB Technical - How do I wire day running lights?

I want to put driving lights on my on my 78 to use as day time running lights. I would like to wire them to come on when the car is started. This I can do, but I would also like them to go off at night when I dim the headlights so as not to blind on coming cars. They should stay on when lights are on bright.
How do I do that? Thanks for the help.
Jimmy Chew

Why the **** should you want to do that? Leave it alone and don't annoy other road users. It is only easy to see a car with its lights on during the day because we others have ours off. If we all had our lights on there would be no advantage - except to the oil companies and spares manufacturers. So don't be so selfish. I have as much right to be seen as you!
ian thomson

What's the matter Ian? Bad day?
Steve

Jimmy, I have a plan for such a setup provided to me by Bob Wilson, a frequent visitor to this site. I will post to you via email, and you can see if this is what you want to do. Bob's setup is a bit different than usual in that it runs the low beams at a slightly lower voltage than normal, making them still plainly visible, but not annoying as Ian dislikes. Also, this allows the low beam filaments to have a bit longer life than they would otherwise.

Anyone else who would be interested in this modification can email me and I will pass on his info.
Bob Muenchausen

Ian ---

There are some conditions here which you may not face, making daytime running lights a safety issue.

There are a few 3-lane roads in this country: one in each direction plus one for passing in both. The ability to see (and be seen) in that passing lane before another enters from the other direction adds to one's longevity. The same is true of two-lane roads which are more common in suburban areas.

In coastal areas, like San Francisco and San Diego, there is often restricted visibility nights and mornings. If I can't see cars from the other direction, at least they can see me.

(DRLs have become standard equipment on US-made autos).
Dan

Slight correction for our friends in the UK - DRL's have become standard equipment on MANY US cars. Notably GM cars, who has made them standard throughout their range, adapting the system required in Canada. They have been required in Sweden, too, I believe.

There is quite a bit of controversy about them. Most drivers, if forced to choose, don't like them. Many people think they're wonderful. They do permit visibility in twilight, and rain and fog when many people don't automatically turn on their lights. On the other hand, I've noticed that under bright, sunny days, sometimes the running lights will tend to camouflage car amongst all the dazzle and glare. I've seen that happen more often with a motorcycle than a car, but still, DRL's can make a car LESS visible under certain conditions.

Nothing comes for free.

If you'd like to go the daytime running light route, it may be best to retain manual control, but rewire in such a way so that the lights are off when the ignition is off.
John Z

There is a discussion and wiring diagrams for a DRL setup similar to what Bob is referring to on the excellent MGB Electrical Systems Pages of this site.
see:
http://www.mgcars.org.uk/MG_Elec-Tech/drl.html

...Ron
Ron Bland

I believe that it is the extended winter of the more northern latitude of canada which is responsible for the All-Canada legislation. Here in BC, where we have much rain and mist and fog,( rather like UK?) it is very sensible. I have been told that some of the northern US states also have this legislation, for the same reason. My '71 has the low beams coupled with the marker lights, and i assumed that this was a PO mod. Now, i am not so sure. They are, of course, manually lit with the first detent of the light switch.
Ken R
Ken Rich

John Z makes a good point about DRLs making a car Less visible in certain situations. Stelth technology for aircraft have put lights on the aricraft to make them harder to see during daylight flying. Still and all, I do run most of the time with my headlights on during the day. I feel that anything that might make the car more visible to others is worthwhile. I have however taken a low tech approach to the control of the lights - a trained right hand. Cheers - Dave
David DuBois

You mention stealth aircraft with lights --- but it became common for US Navy squadrons to adopt a procedure to turn lights on below 10,000 feet in about 1964. The main object was to be seen by bug-smashers with their cloud-colored paint.

This was eventually adopted by the airlines and was expanded to all operations below 18,000 feet.
Dan

Same thing has been done with tanks. Surround the outline with lights, put it on a hill top silhouetted
against the sky and you can 'see' the tank vanish and reappear as the lights are turned on and off.
Paul Hunt

I run PIAA driving lights on my B you can see them during the day but at night they REALLY light up the road. The PIAA lights are expensive about 400 for set but it comes with a harness and every thing you need to hot wire it from the battery But I set it up so they lights go off with my high beams and can be on or off with my normal lights.
Ross

Another thing you can get it a little LED light clip for your H4 bulbs and they LED lights up during the day and off with your head lights its all you need during the day. Another thing you can do is make it so your H4's draw only a little bit of current like 5 amps with the ignition on
Ross

Bob Wilson's info pretty much follows the guidelines presented by Rick Astley's site given above. Bob has a very brief but well written outline of what he has done, and then a decent drawing to show how it is wired. Bob had been tinkering with this system for some time on his Volvo, and has it pretty much down to a science. Again, if anyone wants copies of these, let me know.
Bob Muenchausen

Just for the info. I picked up a set of Halogen headlights extremely cheaply from Little British Car Co. they came with a smaller bulb (european style) in the lens. The lights can be wired to your existing light system so they turn on on the first position of your light switch. Call Jeff at LBCC and see if he still has these in stock. I think I paid around $50 for both.
Luis

I wouldn't want any lamps on while starting the engine.
You could wire them to the accessory switch to prevent this and use a relay that is grounded though the headlamps to turn them off when the headlamps are on.
George B.

Jimmy,
The one disadvantage already mentioned is having the electical system having to cope with powering tha lights and start the engine simultaneously.
If I were doing it I would add an extra circuit to the set up so the choice is: Park, DRL, Main, High.
******************************************************
Dan,
I see you have been suffering with the dreaded "centre passing lane", also know here as a "suicide lane", too.
These are here mainly due to the distances involved and the realtively low volume of traffic and are universally hated and despised.
They are thankfully being replaced as roads are upgraded and are no longer built.
******************************************************

Peter Thomas

I find it nteresting to hear of the differences in other parts of the world. In UK we did away with those 3 lane roads a long time ago for the same reasons people critcise them for. Talk about suicide alley! However, my thesis that having your lights on permanently is selfish still holds. Sure if visibilty is down or you need to be seen for another reason put your lights on. Thats what they are for. I don't even question the logic of having special low power daytime lights per se, just the fact that they come on with the ignition. If I need my lights on I put them on - and put them off afterwards. To have them on all of the time, even when not needed is wasteful and sloppy. I don't need some car regulator, or manufacturer to tell me when I need my lights on. Such prescription on their part assumes that I do not have the intellect to put them on when needed. I will not attempt to argue that you cannot be seen better with lights on than off; though I find the idea that it may even be counterproductive sometimes persuasive. My point is that even if you can be seen better it is _only_ because others have theirs off. If we all had our lights on there would be no (or little) advantage. By this reasoning your inhanced safety is at the expense of those of us who do not have our lights on - and that is selfish. So keep your lights off until you need them and then make a rational/logical decision to switch the bloody things off again.
ian thomson

Ian

I am afraid that I find your logic flawed. You say that if everyone has their lights on then any individual motorist will not be noticed. This is a non-sequitur. Car lights are not used to distinguish a particular motorist from all of the others. Lights are used to make any motorist who is using them more visible to all other road-users. For instance how is it that I am able to notice headlights of on-coming drivers at night when everyone else also has their lights on? Are you suggesting that in foggy conditions your car will only be visible if all of the other drivers keep their lights off?

I think that your reasoning is perfectly sound - but only in the context of schooling fish, flock of birds or herding Wildebeest where large groups of similar looking individuals find that there is an evolutionary advantage in looking as much like the next guy as possible. However, when it comes to troupes of MGBeesties I think that a more preferable objective is to be noticed rather than not to be noticed.
You may like to test this by driving around the countryside tonight with your lights off for an hour or so if you can make it that long. Geddit?
Marc Gander

Marc. I must point out what I said about half way down my piece viz. " I will not attempt to argue that you cannot be seen better with lights on than off". By this I mean that I concede the case that the person who has their lights on can be seen better than the person with their lights off, though I was interested in the arguments against this put forward by others. My point is that when we all have our lights off in good visibility we are all on an equal footing: we can all be seen equally well. I am only talking about good visibility here as I also said " Sure if visibilty is down or you need to be seen for another reason put your lights on. Thats what they are for". However, if somone has their lights on then, all other things being equal, they are putting me at a relative disadvantage unless I put my lights on also. And the more people who put their lights on the more of a disadvantage I am at if I keep my lights off. When all but me are illuminated (in good visibilty remember) I am at the maximum disadvantage and am forced to join them in order to be seen at all. This is because by this time all we are seeing on the road are lights and those without lights are rendered relatively invisible. At this point we are all once again on an even footing, all equally visible, which is where we were before any of us reached for the light switch. In my opinion wiring the lights permanently to bypass the drivers conscious intervention creates a tendency for us all to move towards this ludicrous situation. All it takes to bring this about is for enough car manufacturers to sell this as a "safety feature" or for legislators who think they know whats best for us to enshrine it in law. Ultimately the only people who gain are the bulb and alternator manufacturer.....oh and the politicians and Car manufacturers.
ian thomson

Ian,

Get a hobby! Something other than ranting about headlight use! Maybe try and get a lady in your life? You know I always like a lady that had her DRL's on.

Cheers

Todd
Todd Budde

Interesting. Let me add one more factor:

Some insurance companies, including mine (USAA), make modest reductions in cost when DRLs are installed. Do insurance companies do this based on some evaluation of safety enhancement? Or are they merely performing a random act of generousity.
Dan

Many (most?) daytime running light systems have a cutoff switch for starting so the lights are consuming power during startup. On cars with an automatic transmission DRLs don’t function when the car is in Park and on cars with manual transmissions the DRLs don’t light up while the hand brake is set. General Motors did run some ads that said they were including DRLs on all their vehicles because the safety of their customers is paramount. HA! They can’t fool me, they are doing it because Canada requires DRLs and it is cheaper for them to drop production of the wiring harnesses without DRLs than to continue to produce both.

For anybody interested in this topic I suggest you take a look at this site http://www.howstuffworks.com/question424.htm. http://www.howstuffworks.com/is a great site anyway, but question 424 applies to this discussion. The question is, “If daytime running lights were mandatory in the U.S., and all vehicles had them, how much extra gasoline would that use each year?” The answer is long, but the punch line is, “If daytime running lights were on all the vehicles in the U.S., we would burn an extra 406 million gallons of gas each year… …Looking at it another way, an extra 8 billion pounds of Carbon Dioxide would be added to the atmosphere by this law.”
George Champion

The only differance between a canadian GM and a US one is a head light moduel it is very easy to make a US car have DRLs
John Bucannon

The argument at the "How Stuff Works question 424" about the fuel cost of headlights being on did not convince me, because of a possibility it left unaddressed. It assumes that any increased draw on the electrical system necessarily requires more engine power. But, perhaps, particularly at speed, there is excess electrical power available. If that is so, then the headlights would be drawing power that is otherwise wasted, and thus the calculated fuel costs would be way too high. Does anyone know if this conjecture has any validity?

In any event, it is likely that most safety items entail some tradeoff or cost, and the question is whether that cost is worth the benefit. (Someone could also calculate the fuel cost of air bags, which add weight to the car at all times.) Without knowing the safety benefit, the cost of 406 million gallons of gasoline plus extra atmospheric carbon dioxide is impossible to evaluate.

Ian accused the users of DRLs of selfishness. Perhaps users of seatbelts are selfish too, because, knowing they are safer, they may drive more carelessly, endangering others. Is seatbelt usage selfish?
David Cushman

Even tho I have driven for almost 40 years without the benefits of daytime lights and have learned skills to compensate for the lack of them (we never really thought about lights, we just watched for cars in the many ways they appear under varying lighting conditions!), I must say that any car with them does indeed get my attention a bit easier than one without. I think it was the recognition of this perception phenomenon that prompted the adoption of these daytime lamps. I only wonder if the the use of them has a counterpoint for drivers not used to perceiving cars without them?? In the US today it is such a mixed lot that it is not a problem, but if they did mandate ALL cars to have them, then, indeed, I think there might be a dependence on them and some recognition ability would be lost among drivers. Probably a pretty esoteric response, but a lot of what causes accidents are the differences in how people perceive the world around them - both by individual differences, and in learned ones too.
Bob Muenchausen

Dan. You are right insurance companies are not in the generosity business, but they are in the marketing business. The modest reductions are just an "edge" in a very competitive market, much the same as the fitment of lights themselves and claims to safety are to the car manufacturers. George illustrates how manufacturers act in their own interests in ways which can have far reaching effects on the users. This aspect of the argument/discussion can be seen more clearly in the case of airbags but to go down that route would be getting even further away from MGs than we are now and I apologise to the list for having used it for arguing what must be for some a dry and unnecessary case.

David. You are absolutely right that there is excess power available at speed, and even at lower speeds with a modern system, but it is available only as potential power. That is: the power is only produced when it is demanded. One of Newton's laws talks about this I believe. If you want an illustration turn the headlights on while at tickover and hear the slight change in engine note as the load on the alternator increases. The alternator becomes harder to turn and in turn slows the tickover slightly. Thus the engine needs more fuel to maintain it's speed. In this way more electrical load demands more fuel. The argument does not apply to seatbelts in the same way. There is an argument which states that seat belt usage is likely affect the way the user drives negatively but there is no mechanism here for the direct effect of seatbelts on other drivers. The use of seatbelts can not therefore be considered selfish per se, although the method of driving which they may create perhaps can.

Bob. You have got the nub of my point. What I am saying depends on us finding the odd one out more difficult to see as more people have their lights on. If this does not occur then my argument falls. There will, I believe, be a critical mass of "lights on" at which we will all have to follow suit in order not to be disadvantaged in the safety stakes. At low levels of headlight (or other) usage it is not a problem but this sets us on a slope which ratchets us towards permanent, and unnecessary, headlamp usage. This becomes inevitable if the politicians and manufacturers see personal advantage in promoting it.

ian thomson

I just read up about generators. They are indeed harder to turn when producing power, and the reason is that current in the wire that is spinning inside the magnet generates a magnetic field around the wire, which works against the magnetic field of the magnet.

Ian, you are right that the seat belt example is not the best for making my point (unless the more careless driving response is automatic in humans). Many things that individuals do have spillover effects on others, for which it often would be difficult to provide compensation. Should we avoid all such activities? You presented the argument that the DRL (when used where not everyone is using them) is possibly one such situation. Here's another: burglar alarms. If I have an effective one in my car, then probably thieves are more likely to steal someone else's car. Am I therefore selfish? Should I not have one installed to avoid this charge? I guess I don't find the "selfish" label very useful in analyzing these issues.
David Cushman

Now that we have disposed of the Daytime Running Lights issue . . .

About 30 years ago while in Tokyo, I noted that when their autos came to a stop at a traffic light, their headlights were extinguished and came on again when they began to accelerate from the intersection.

Have I thrown a bone amongst the hounds?
Dan

Thanks for the comments.
Bob,
Thanks for the help.
Jimmy Chew

Hello Boys

I don't know about you, but I think Ian Thompson should get out more....

Happy Motoring - and don't forget :
Safety Fast

Lesley from London
Lesley

This thread was discussed between 14/05/2002 and 19/05/2002

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