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Triumph TR6 - Wiring Driving Lights

Has anyone out there wired up a pair of driving lights. I ve located a nice pair of original Lucas driving lamps that I would like to use as daytime running lights and at night in combination with main beams


I have read Dans chapter on wiring extra lights but would prefer to wire them on a seperate on/off toggle switch rather then from the main beams switch. Am I able to take a feed from the main beams (parallel circuit) or should I create a new circuit and if so...detailed guidance is appreciated so I dont short my car out when I turn the lights on.

thanks

bob


Bob Craske

"Am I able to take a feed from the main beams (parallel circuit)"

NO! This is a sure fire (pun intended) way to burn your car down.

"or should I create a new circuit and if so..."

Yes, this is the way to go.

Wire them as shown in my book, but instead of feeding the switch or the relay from the blue/white wire from the headlight switch, feed it from a green wire (if you want the lights to operate only when the key is on) or from a purple wire (if you want them to work with the key on or off).

If you wire to a green or purple wire, you won't need the fuse shown, as the green and purple wires are already fused. You'll still need the fuse in the main power lead though.
Dan Masters

Thanks Dan

so..if i get this right

From the green gets me working driving lights when both ignition and new switch are on..thats good.

so I take the green to the switch. any green or a specific feed and do i then splice that feed to maintain both circuits (original and new lights)

...from the switch I run a new wire to the actual lamps (or do i run two wires, one for each lamp?)

grounding of the lamps...do I just ground to the body or do i need to run a special ground?

last question (sorry if its not!) when you describe a fuse in the main power lead...which of these wires do you mean? I had thought of in line fuses somewhere in this circuit?

thanks



Bob Craske

Bob,

From your comment re: "Dan's chapter," I assumed you had a copy of my book. If you do, the wiring diagrams are on page 171. This requires a relay for operation. If you don't have a copy of my book, let me know and I'll send you the diagrams after the holidays (I'll be in Atlanta for Christmas).
Dan Masters

Dan

I have your book but do not really understand the diagrams...

I would like to hook up these lights on their own circuit independent from existing light switch so i can use at night in conjunction with main beams and during the day as daytime running lights

I found both the single and double pole switches at the local store..but couldn't find a relay..is that still needed if I am doing a seperate circuit and if so, is any particular model of relay is needed?

I am very naive with wiring (despite your excellent book) so would appreciate if sometime after the holidays you could draw up a simple diagram showing exactly how to hook this circuit up including showing all connections/sources and end points (all part labelled). I will use in line fuses as well or if you think necessary, i can run the new circuit through the spare fuse slot in the main fuse box.

Thanks again and merry xmas

bob

Bob Craske

Bob,
Til Dan gets back, maybe this will help.
It is highly advisable to use a relay for this purpose.
On page 171 (diagram C) shows terminal positions (the left diagram), and a schematic of what is actually goin on inside the relay and switch (the right diagram).
You say that you do not want to depend on the headlight switch to run the DL's. Then you can supply power to the coil of the relay from a white or green wire as per the chapter on power distribution. This will in effect give you DL's only when the ignition switch is ON. White wires are "switched and UNfused", and Green are "switched and Fused".
You still need a high current wire from the fuse box to your relay, or from the battery post (fuse inline) to the relay, to supply the main power for the lights themselves.

According to this link on MG electricals (I know, I know, no sneers please), the ISO relays are commonly available at Canadian Tire. Radio Shack has them too, but I do not know if you have those in your area.

http://www.mgcars.org.uk/electrical/typerelays.html

You may want to check out the info on Daytime Running lights on this site, as it has a lot of helpful info regarding reduced voltage for daytime use, and normal for nightime use.

Hope this is helpful to you.

Mark Riddle
Mark

Mark

Thanks for the assist, I think I am starting to follow this now,,,

I have located the SPDT switch (16 AMP) and Relay (12VDC, 160mA, 66ohm. Contact/rating: SPST, 30A/12VDC.

when you/dan state supplying power from a white or green...thats where i get lost, how do a "jump" off of that wire with out disrupting its original circuit?

since I want to run lights manually and only when ignition is on, Can i can take the green from the main dash harness that would normally supply OverDrive circuit (which I dont have) as depicted in figure 18 (pg 104) for the 73-76 TR6?

if so, i then run that green (which is fused) to the coil on the relay (depicted pg 171 diagram c as "powersource see text" connecting at "87"

now i get more confused...from the relay I run to a switch but since I dont want my driving lights associated with the main light switch, how does that switch get powered without having the "blue/white" from the headlight switch.

I really need a spelt out diagram showing connection points throughout and sources of power as well. Can someone wing one together and mail to my link, pehaps a more obvious visual will turn on the light bulb :-)

thanks

bob
Bob Craske

Do you have a voltmeter? A 12 volt lightbulb with a couple of wires soldered on to it? Have you used a soldering iron? Shrink tubing?

Make sure you have power where you want it and when you want it. Your test lamp or voltmeter will register when the ignition is on, but not when it's off. I think (please correct me if needed guys) you run unswitched power (big wire) to the relay, then out of that (another big wire)to your lights. Find the shortest safest route for this from the fusebox or battery, maybe use a few zipties to keep the wires in place. Use logic when choosing a place on the fusebox to tap from, you don't want to overload what's already there. The lights won't come on until the switched (by ignition)switch tells it to. Make sure your lights are grounded well, surely the relay case requires a ground too, so don't screw it into plastic. Make sure the wires and switches and relay will handle the load. (Using a relay, your switch won't require big wires, all it does is make the relay work, not a big load, which keeps that big wire out of your dashboard) The big wire will go to the relay and out again, controlled by a little wire from the switch.

Maybe go to the auto parts store and look at the instuctions that come with the driving lights. They should have a real simple diagram that will make this all look easier. Maybe even the clerk will have a bit of advice. Another source of info might be a car stereo shop.

I'm no wiring expert, so I'm open to corrections here. I don't want you to cause the smoke to come out of your wires, either. They might not work after that. Don't use any 3M splicing connectors (or worse), solder your connections, use heat shrink tubing over that, and even silicone over that if you want. I'll also let someone else tell you what gauge wires to use and if there's an unused fuse in the fuseblock, I don't know.
Tom

Bob,
As you suggest, the OD supply circuit would be a great place to "source" power for the relay coil. It is fused, and ignition switched.
This is not a good place to "source" the power for the lights themselves however.
You will need a bullet connector to connect your wire from the OD circuit connector, to the coil of the relay (#86). If you choose to place your switch in this line, then do so. You could also place it in the ground side of the coil, by wiring from terminal #85 of the relay, going to the switch, then from the switch to a good ground point. Either way will energize the coil when the switch is activated. The wire for the coil circuit as outlined above does not have to be of a heavy gauge, as the current for the coil is quite small (12 volts/66 ohms=180mA). A 16 or 18 gauge wire would work here.
The relay itself should be located somewhere in the engine bay, preferably near your supply source for the lights, or near the lights themselves.
Not knowing what current your lights draw, I can only suggest that you connect directly to the positive terminal of the battery with a 12 gauge wire as Dan suggests (good for 20 amps). You should use an inline fuse in this wire, and connect it to the #30 terminal of the relay. Then run a 12 gauge wire from terminal #87 of the relay, to the positive connection(s) of the lights.
If there is a ground wire on the lamp units, these should be solidly connected to a good ground with a 12 gauge wire. If there is not a ground wire, then the lamp housing itself should be well grounded to whatever mounting point you choose to mount them.
Again, as Dan tells in his wonderful book, all the above connections should be both mechanically and electrically "solid".
There are many variations in the above plan, depending on where you source power from, and where you place the relay and switch.
This is a very basic layout, but it will get you going.

Any other suggestions Dan?

Cheers,

Mark
Mark Riddle

Mark/Tom

Thanks for the help

I stopped at an auto part store and found a 30 amp relay, a illuminated toggle switch and a feed connector to source main power from the battery post.

now the trick, the parts guy described running the power from the battery post to the switch, then to the relay. I did nt like that since it sounded off from you and dans suggestions so I put the stuff back on the shelf and decided to come home and think more.

so..sorry but here I go again

I will find a green (fused) line (like the OD feed) and run that to my toggle switch. From that switch (which is also grounded) I run a medium gauge (16/18) to the relay and attach to point 86 on the relay.

From the battery I supply main power to the relay attached at #30 or # 87?? (Mark states 30, Dans diagram states #87), and this is a fused connection (30 amp).

From the relay, I have 1 or 2 connections (the one in the auto store had two "outs" / 5 blades on it) # 30 in Dans diagram and # 87 in Marks description...which one, I guess the answer to the point above solves this question? These run to the positive wire of the lamps.

These are beautiful 35+ year old original Lucas driving lamps, I can guess they will draw around 30amps. I will ground them to the frame.

The relay is also grounded to the frame.

Sounds right to me after listening to your descriptions and seeing the relay in my hand. Can someone confirm the answer regarding the confusion re reversed descriptions of using #30 versus # 87.

also, since the green feed is already fused and the relay feed from the battery is fused, i shouldn't need any additional inline fuses between lights and the relay should I? (overkill :-))

again, thanks all

bob



Bob Craske

Bob,
As to connecting the main power from the battery to the relay. Truly it can go to either of the terminals and accomplish the same task. The #30 terminal contacts the #87 terminal when the relay is energized (when the coil is turned on by the application of power from the switch). With #30 and #87 "connected" to each other, the main power will flow from the battery to the lamps. According to the Nation Relay Manufacturers Association, it is common practice to apply the posotive potential (12 vdc +) to the "common" (#30) terminal, and the "load" (lamps) to the "normally open" (#87)or "normally closed"(#87a) contact. If you wanted to have power going to the lamps when the relay was "off" (coil not energized/switch in off position), then you would connect the lamps to #87A. But obviously this would not be the most desirable situation as the relay "coil" would be have to be energized durring the vast majority of your driving time (daylight hours). So the #87 contact is the place to connect to, allowing the auxillary lamps to be "powered" at the same time as the switch and relay coil are "on".
There is a reason that comes to mind for going Dan's route and connecting the battery wire to the #87 terminal instead of the #30, there will be no voltage present on the #87a terminal when the relay is "off". Outside of this, either scheme will work.
As for the fusing, you are correct in your assumptions. The green wires are already fused, and the main power wire from the battery should have an inline fuse in place.

Does this help any?

Mark
Mark Riddle

Mark

Thanks, that pretty well confirms everything as laid out so...I am off to the auto store even though its - 15 outside! Just cant wait to get started :-)

bob
Bob Craske

Mark

I cant locate that "spare" OD green wire feed under the dash, probably not there or buried in a maze. To power the switch, can't I take a feed from the same green side of the fuse box since there are two blades on that side of the fuse box and only one in use? (I am assuming both blades are protected by the same fuse and are hot, just like the two purples wires below it)

If so then its only a short 3 foot run through the dash grommet to the light plinthe, where I can drill a small hole and mount a nice chromed toggle switch beteen the heater fan switch knob and the heater control knob.

thanks

bob

Bob Craske

Bob,
That is a very good place to source your relay coil power from.
Run from the fuse, to the relay coil terminal (#86), then a wire from terminal #85 to one side of the switch, then from the other side of the switch to a good ground.

Mark
Mark Riddle

Mark

I was thinking of running to the switch direct and following the schematic we laid out above..

1: green power source (fused) from fuse box to interior toggle switch. (operates only when iginition is on)

2: switch feeds to relay (energizes)

3: seperate feed from battery (30 amp fused) to relay #30

4: the relay I have has two 87 posts to the lamps themselves


I thought that the lamps probably require higher gauge and that putting the lamp feed on that fuse rather then the switch would be too much for the exisiting wires/fuses.

thanks

bob
Bob Craske

Bob,
Your plan will work fine.

Mark
Mark Riddle

This thread was discussed between 23/12/2004 and 17/01/2005

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