Electrical question - headlight relay needed?

[767Jockey]

I'm going to be using a Lucas three position toggle for my headlights (off - parking - on). I know using a relay can't hurt, but I am an electrical neophyte and I would like to avoid the complexity (and cost) if I could. Are any of you guys using original type Lucas toggle switches for your headlights and parking lights lights running without relays? I am only using regular sealed beams, nothing fancy up there. Can the Lucas switch handle the load of the headlights and the parking lights without a relay? Thanks.

[Rick Parker]

Noooooooooo

[767Jockey]

Originally Posted by Rick Parker

Noooooooooo

Noooooooooo.......what?

[Garage10]

Hey 767
Check out madelectrical.com as it explains a lot about wiring and relays. You will want to use relays.
Good luck
Brent

[Rick Parker]

Jockey:
I was answering both of your questions with the same answer.... Do not attempt to run the current for the lights directly through the switch alone. The low beams pull 8-9 amps, and the high beams 13-15 amps. Add to that the parking lights and you have a potential 20 amp load through the switch. Not a good thing. Also be sure to use wire of correct gauge based upon length of the wire run and maximum anticipated current load if in doubt us larger size.

[767Jockey]

Originally Posted by Rick Parker

Jockey:
I was answering both of your questions with the same answer.... Do not attempt to run the current for the lights directly through the switch alone. The low beams pull 8-9 amps, and the high beams 13-15 amps. Add to that the parking lights and you have a potential 20 amp load through the switch. Not a good thing. Also be sure to use wire of correct gauge based upon length of the wire run and maximum anticipated current load if in doubt us larger size.

OK, thanks. I was guessing that was the answer. It's a brand new Ron Francis harness, so I am assuming they used the correct size wire. I'll pick up their relay kit. That'll be the 6th relay I have in this little car. This electrical system will be a work of art by the time I'm done with it.

[Rick Parker]

Much more reliable with less voltage drop if you use the relays.

[undy]

Bosch makes 50 and 100 amp rated 12 vdc relays that work great. I use them for any relay I need on the car. They have screw-lug connections, unlike the "voltage drop waitin' to happen" spade connectors of the average aftermarket automotive relay. I get the relays from Waytekwire.com

[strictlypersonl]

The actual current draw for a pair of 6014 (50W/60W) bulbs is 8A and 10A respectively. Each parking light draws 0.6A for a total of 2.4A. So what we're talking about is a maximum total load through the switch of 13A maximum. The original switch was used for many years without a relay. Switch failures have been almost entirely mechanical, not due to excessive current.

[RICK LAKE]

strictlypersonal Mr. Wizard I agree with the switch is designed for a 20 amp feed. The question is when the system is first turned on, what is the amp ratings for that .2 sec? Years ago I used to run alot of aftermarket accessories, Fog lights, electric fuel pumps, big amps, and compressors. About every year 1 or 2 of the switches would go bad. I would pull them apart and find that their internals where melted and the contacts cooked. Every since that time and adding electric fuel pumps, aux cooling fans, accusump oil tank for preoiling to my cobra they all have relays of either 20-30a or 30-40a ratings. It's the spike of turning on the power and not the steady load of the curcuit running. The relay contacts are twice the size of a toggle switch and can hand the loads alot easier. New cars now have 20-40 relays built internally into the fuse blocks just for this issue. Will your system work without a relay, YES. Mine has the same switches in it from 96 without any problems. Your wiring harness with good ground contacts and the correct wire sizes will not cause a problem. For another car line I wouldn't say the same without seeing the wire ratings and switches. A relay weight is 5 oz. and 4 or 5 wires needed for the curcuit what's the added harm in adding one? Rick L.

[priobe]

If I might share my .02

The reason for a relay is minimize current throught the switch and to provide maxium voltage to the unit. The switch will be able to handle the current, however over time with out a relay you will be developing more carbon on the contact from the higher current(without a relay). So in the long run your switch will fail mechanically because of the contact but was cause from not using a relay.

[Jerry Clayton]

actually its the arc when you turn off the power that kills the switch

[Larry N Johnson]

We have used Lucas switches from Finishline.
the 3-position for off-running-head
the 2-position for high-low beam

Here is how we wired the relays:
Wiring Lights

Hope this helps a bit.

[lal Naja]

Does anyone know how many amps can be safely switched by the foot operated Hi-Low beam switch found in a lot of 50tees 60tees and some 70tees cars/trucks I have one of these switches on my Cobra but I cannot find any volt/amp rating rating. Do these switches require a relay? Or are they built tough enough to handle the job.

Look forward to your comments,

Thanks,

Arthur

[RICK LAKE]

lal Naja Art My CJ5 jeeps all have high low headlight switchs from the factory. They are floor mounted. They are hit with mud,underwater, snow, salt, and stepped on about 500 times. Lighting in a CJ is poor with only, get this,a 37amp Alt. They all have relays also. I think the switch is tuff enough to take the spike hits but IMO adding a relay is a better, safer, way to go. I would see if you can find a heavy duty switch. This would be in medium duty trucks for low beam, high beam switching. How many terminals are on your switch, 2 or 3?? If 2 it's just a single feed curcuit, if 3 terminals this one sends power out on 2 different curcuits and cuts off the other one. It depends on the headlight wiring. Some cars run either low beam or high beam only. Other cars run low and high beam at the same time. Old sytle lights this is fine. The new Halogens will cook wiring and melt lamp housings or any plastic thng in the area without a vent to cool the lamp. The new Zeion lights are great for repair shops. We get between 2 -4 hours to rewire the curcuits on burnt out harnesses. Lastest was 1,400.00 dollars and 6 hours of work. The kid wanyed the car to look cool. Rick L.

[lal Naja]

It's a 3-wire switch and I think it would have been okay with the original sealed-beam headlights. I have upgraded to 100/90 watt halogens, so I'm going to change the headlight wires in my harness to thicker gauge wires and If I'm going to do that, adding a relay would be a no brainer.

Your suggestion for a vent for cooling is probably a good idea too. I think I will cut some slots in the top & bottom of the headlight metal buckets to allow some air circulation. Normal convection will allow air to enter from slots in the bottom to flow out from the top.

Thanks,

Arthur

[RICK LAKE]

lal Naja Art I want to give you a couple of reasons for not running this high a bulb.
#1 Most states allow a 55/60W limit on bulbs any thing higher and you can blind people ahead of you driving at night. NJ hands out tickets for this. The blue zenion lights the cops love to see unless they are in MB,BMW, or Honda.
#2 heat is big in the small area they are in, melting buckets if run a long time is common. I have tried all kinds of ways to control this problem. At highway speeds the heat is removed enought to not melt things. No air flow like stop and go traffic and they cook. Drilled holes into the lens, the problem here is if you run in the rain or get condensation in the lights, I drop of water will blow the bulb if hot. Condensation also happens at night and after to turn off the lights and like you said the hot air goes out the top and the cool air comes in the bottom and you have water mist back inside.
#3 We talked about the wiring and relays.
#4 I do run illegal light on my motorcycle for 2 reasons, first driving at 75mph on some roads to help see animals at night. There are also some DUMB drivers out there that cut you off and say they didn't see you, not with my bike.
good luck with your decision, just remember the next dope that has illegal lights on in his car following you and how they cause you to have driving issues. These lights where for off road ONLY usage It states it on the box they are sold in. Rick L.

[lal Naja]

Thanks Rick! Good points. This is all new to me, so advice is much appreciated.

Now that I have the H4 kit, I can try various wattage bulbs and find the wattage that works best for me and oncoming traffic. The kit I bought came with the 90/100 and you're right, that may be over kill. I have no prior experience with headlights & their attributes.

With regard to my headlight buckets, (perhaps I'm using the bucket word incorrectly. Mine are metal, and these are the shape of a 'Cone Head' like Dan Akroyd in Saturday Night) the headlight/sealed-beam fits into these. So I guess I won't have a melting issue. Cutting vents in the top & bottom of the buckets could help with overheating. Do you still think that moisture would still become a problem. The headlights have rubber seals where the bulb enters the lens/reflector unit and I wasn't going to drill holes in this component.

Thanks, Arthur