I'm having a debate with a friend of mine. He claims it's mandatory that you have a relay on your wiring for the headlights. I say it's not necessary. In fact, I'm not running one on my truck. I haven't had any problems. I do have an aftermarket light switch (don't know the make, etc) I do notice that when I pull the headlight switch all the way out. The only lights that come on are the parking lights. If I start the truck, the headlights come on and work fine? What do you guys think and what is the difference between a relay and not having one? Thanks. Ed

 

Lower

Lots of cars do not use a relay. Is it a good idea? I think so. Takes a lot of stress off the headlight switch in a typical wiring schematic. Run 14 GA or better yet 12GA off your relay to the lights and they'll work great. Very noticable improvement over stock in some cases. There is a tech article on FTE.

 

Fatfenders, are saying it is a good idea to have a relay? Your statement is a little confusing, or maybe it's me?

 

Lower

Yes, I believe it is a great mod. You need a couple Bosch style relays from the auto parts house. Check out the tech section for the article. Let me now if you can't find it. We can talk you through it. What it essentially does is turns your headlight switch into a low amperage signal device for the relay. Rather than running all the juice through it to drive the lights. The big wire stays under the hood. Headlights brighter, headlight switch lasts for 300 years.

It's less necessary on some vehicles than others. Some Ford trucks from the 80s I think had real lame headlight wires. Like 16GA I think. You get a voltage drop and heat build up if the wire isn't sufficiently heavy.

 

If you upgrade from sealed beams to H-4 or HID headlights, a relay is a must unless you own stock in a switch company. The higher draw of the bulbs will cook the switch in short order. If you see your headlights going off and on for no apparent reason when using high beams, you need a relay, quick!
Using a relay will never hurt anything and may often help.

 

I was afraid you guys would tell me this. I hate electronics. I wired the truck myself and used 12GA to wire the headlights. As we speak, I went and checked the switch because I was wondering why my headlights wouldn't come on without the ignition on. Looks like one of the wires went to the ignition switch side instead of a constant hot lead. Fixed that! Now you tell me I need relays. LOL..... Really don't want to install them but..... Oh, Fenders, I did find the tech article on the relays. Between me and you, I don't care if my switch last 300 years because I won't be around to see if the switch is still working. LOL... Thanks. I know it's probably easy, but I'm lucky to figure out whats positive and negative, let alone figuring out what the numbers on the relays mean and where they are suppose to go.

 

I'm a firm believer in relays. When I ripped the interior out in my 56 last winter I re-did all the wiring at the same time and put them in for things like the aftermarket wiper motor, fuel pump, electric rad fan, etc. and used those 6.00 relays you can get at any auto parts store or JCWhitney. They come with wiring instructions an 8 yr old girl could figure out .

Of course they are not absolutely necessary, but they save a lot of switch replacing down the road and by golly, I got a lot of switches .
Norb

 

A relay isn't difficult to wire, it's just an on and off switch turned on and off by another switch instead of by a handle. If you can wire an on and off switch you can wire a relay. Just because it has a different name don't let it spook ya.

 

I say it comes down to how bright your headlights are. If the wires and switch can handle the load, then your lights will be good. Last year, the first time I took mine out at night, I noticed the lights were not very bright. And the longer we drove around, the weaker they became. (heat build up) I followed the FTE tech article instructions and mounted the relays. Now the lights are bright and Mama don't complain nomo! Not everybody uses relays, but you should if you get better night vision. We don't want to see any dents in your effie! There are several posts from last year as well that give specific details on installation techniques. Somebody reported that their light switch was very hot without the relays. This is a switch that will fail in a hurry. Good luck, John

 

thanks for the advice everyone. I'm gonna look into putting the relays on this weekend. I guess it's a good idea to do both low and high beam. I'll let you know what happens. I'm running standard seal beam halogens so the relays might be a good idea. I just hate messing with wiring but I feel I'm better off doing it by what you guys say. Thanks again. Ed

 

I know I overuse this saying, but here we go again..."cheap insurance". I'll be using relays if and when I get to that point.

Ron

 

Relays....sound like a great idea. "Works better, looks stock from 10 feet away".

Think I'll try it in my F-250.

ROB

 

Another "AX in the days" tale:
I had a then new 67 Tempest (baby GTO) with my first set of dual headlights that I tended to drive a "might bit" over the speed limit on dark country roads at night. I discovered thru a friend that worked on private planes that the landing lights for a piper cub (I think) were sealed beam bulbs the same size as the high beam bulbs in my car. I installed a pair and the light output was AMAZING, I could light up a reflective highway sign > 1/2 mile away! The only problem with them is I knew nothing about relays, so I would completely melt the headlight switch if I used them for > 1/2 hr at a time. Fortunately I got them wholesale, so I considered it a small price to pay!

 

Back in the good old days of steel dashes, you could just blow out the fire and pop in a new switch.

One potential delay for you Lower. You'll want to get a pair of Bosch relay wiring harnesses (connector with pigtail wires) and the install will be very simple. Perhaps you can get them locally. If not, all the wiring harness manufacturers sell them for a couple bucks each. Don't try to just use spade terminals. It's a pain in the rear. They come loose and pop off. Bad circuit to have that problem.

 

Aircraft landing lights in a 67 Tempest...now that's funny.

ROB