Relay Wiring for Dummies????

I've got a pair of standard type relays. I would like to install them in my pickup for the headlights. I understand Ford pickup headlights are wired through the switch. I converted my '71 to the new style lights with repalceable bulbs and have been told to use the relays.

I'm not a wiring genius (guess you figured that out by now) and have a couple left over relays that came with some door solenoids. I put a remote entry system and that came with it's own relays and thes are leftovers. Will they work for headlights, and how do I wire them in?

Thanks for the help.

standard relays have 4 pins, I assume that is what you have Dave. One for 12v source, one for ground, one to send power to load, and one signal to activate the relay that comes from the switch. The relay logic should be printed on your relays. Got a pic?

Thanks a bunch Denny!!! You the man around here!!!!!

Those, without a doubt, are excellent diagrams. Just be aware that last diagram is using SPDT relays. With SPST relays terminals 87 and 87a are at the same electrical point (They are internally connected) while on SPDT relays those two terminals are separate.
I had to use SPDT relays when I wired the door lock switches to use the alarm system on my Dakota. I couldn't find them at any of the auto parts stores here in Springfield, but the car audio stores carried them.

My local surplus electronics store has Bosch relays for $1.00 ea. vs Pep Boys $16.00 for the same one.

Double check relays when purchased. Some of the Bosches are only rated at 15 amps. If you wanna go hog wild with amperage, you will need to go higher. Dave stated that he has some spares, so I think he'll double check the amp ratings.

For some great info on wiring, including relays, load distribution points, rear batteries and single vs 3 wire alternators go here:

http://www.madelectrical.com/

Pat

http://www.alanhorvath.com/54chevy/mad_electrical_2.php

this guy has a boatload of info on his site & some is exactly what Denny show's...joe

I used the original wires where they go thru the radiator support as the remote wires and put the relays mounted to the radiator support on mine.

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Originally Posted by NTFDAY

Those, without a doubt, are excellent diagrams. Just be aware that last diagram is using SPDT relays. With SPST relays terminals 87 and 87a are at the same electrical point (They are internally connected) while on SPDT relays those two terminals are separate.
I had to use SPDT relays when I wired the door lock switches to use the alarm system on my Dakota. I couldn't find them at any of the auto parts stores here in Springfield, but the car audio stores carried them.

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So SPDT relays can be used to wire the door lock actuator. Good info and good to know that. Thanks

For more information try this site www.the12volt.com

I found some 40 Amp Bosch relays at Fry's Electronics they also have the matching plug & pigtails.

Summit actually has some relay wiring diagrams on their website. When I was wiring my car I added several - but for the life of me, could not figure them out. It took me hours to understand the principle, and almost a year later - pretty much ---- gone:CRY::CRY:

http://www.summitracing.com/expertad...p=techarticles

When you go to this site, then click "Slide Show" and you will find schematics on how to hook up several items

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Originally Posted by NTFDAY

For more information try this site www.the12volt.com

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Ken, that is indeed one of the best places for wiring info.

I just realized that this was a thread that was 3+ years old!! :LOL:

Funny story about relays and wiring.

I've done a bunch of wiring in the past and have a degree in electronics so I kind of know what I'm doing. Last month, my father in law asked me to wire up an ahooga and an air horn for his new 2011 F350 pickup. I told him that rather than a high current switch, I wanted to use micro switches in his dash that powered high current relays. A much safer solution. We set the date for them to come to our house before they headed south to winter in Texas.

I didn't check the calendar when we set the date... DUH.

I came home from performing in the band on a Saturday evening (actually is was now Sunday Morning). My father-in-law was still up waiting for me to start the project. Since I honor my committments, I started hooking things up. By the time I got to actually wiring the relays, I just couldn't think anymore. I was brain dead. lets see terminal 30 goes here and 87 goes out there, and what the heck is this wire again for. My father-in-law just started laughing at me. I told him that if he didn't stop he would be going to Texas without his horns (ha ha).

I got it done and it worked well but it took a lot longer to get done. The problem was... My wife woke me up 2 hours after getting to bed finally to say "Lets get going - We preregistered to a car show that includes breakfast." I usually enjoy car shows... but that one, I just sat in the chair and slept the day away.

o.k. At least I thought it was a funny story...
Jerome

Here is a diagram for relays.

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Originally Posted by rumrumm

Here is a diagram for relays.

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Another option is to put the switch on the ground side, between 85 and ground, for even lower current through the switch. Battery power to 30, ignition source (or battery power to both 85 and 30 if you want it available w/o key on, like maybe locks, windows or headlights) to 86, and a low capacity switch on the ground side works good.