4 pin relays for headlights

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moparmat2000

moparmat2000

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I am going to be doing the headlight and high beam relay modification. I know how i need to wire it up, wondering about the relays tho.

What amp relays typically should i use. 12V 40A ?? Or is there something else?

I plan on running halogen lamps either sealed beams or H4 type 55w/65w

Thanks
Matt
 
In this constantly downhill chineseonated of a world we have I'm reluctant to recommend specifics, but Hella comes to mind.
 
You're already off to a bad start if you want to use a 4 pin relay.

Spend the money and buy tyco/bosch relays. I refuse to use the chinese relays in my products even if they are 1/5 the cost tyco units.
 
I am assuming a 4 pin relay because i am figuring thats the way i need to wire it up

School me. This is why i am asking.

I am currently assuming,

Headlamp wire from switch to electro magnet of relay,
Othe side of Electro magnet side of relay to chassis ground.

Battery hot with fuse to contactor side of relay
Headlamp output to other side of contactor side of relay.

I planned on a standard 5 pin socket, but only wiring up 4 wires as i described above.
 
Ok, the problem with calling this or that is that terminology and "standards" get polluted and muddy. You would have to go back to "an original Bosh relay" as used in original OEM configuration. So far as I know they were 5 pin, that is 2 for the coil, 1 for normally open, 1 for normally closed, and 1 for the common.

But "other" configurations by "other people has resulted in all kinds of variations

One is to use larger contacts to make a heavier relay, normally open relay, which should be "4." But some makers wire what should be the normally closed pin IN PARALLEL for more current, so you no longer have a "standard" relay

Worse, some of these (some are OEM like JEEP) use LARGER contacts and don't fit some relay sockets

An example of the non standard "big" pins

relay70aHella.jpg


Another "gotcha" Some replacements don't have internal protection diodes across the coil, and it seems (from discussions on here) that some do have diodes that are REVERSED from what should be "standard." "How to tell?" Check resistance of the coil with your ohmeter, then reverse the leads. If the resistance changes dramatically, you have an internal diode. You need to wire it correctly, or it becomes a dead short.

Below is what I know as a "standard" Bosch style relay with diode

IMG_7451b.jpg


You want the diode REVERSE biased (not conduction) so wiring is

85 --ground--marked -- in photo

86 --trigger to coil positive

30 fused power source "coming in"

87 "normally open" meaning the relay is powered to power this contact

87a "normally closed" meaning carries power when relay not powered.

==========================================================
87a is not present in a "4 pin" and is the pin that if present MAY be paralleled with 87 in a "non standard" relay

Like this

Relay_0332019209_Drawing.gif
 
In a word, Google. Wiring diagrams for spdt relays and headlight circuits are all over the web. More important is the quality of relays and even more so is their connectors. Some very cheap junk can be had if you want to go pennies, and ebay, and mailbox. You would be much better off to go to a parts yard and clip some quality components from a factory harness. You'll find either actual Bosch relays with weather skirts or harness connectors with weather boots. Some of the better pieces I've seen came from near the radiator and headlight doors of 86 through 91 Honda Accord. Not easy to get out of a wreck but worth the trouble. Alternative is a enclosure like more modern vehicles have. Typical generic naked components poked under the battery tray/wherever will eventually be corroded just like bulkhead/ battery/ other connections.
 
First of all, Power is Amps multiplied by voltage. P=I x V. A bulb that consumes 65 watts at 14.5 volts will draw approximately 4.5 amps. More or less.

You can get the 5-pin Bosch relay with mounting tabs on Amazon, as well as sockets for them. The relay is Bosch # 332019150. The relays are also available from Summit.

Parts stores that speciaize in parts for imported cars used to carry a Bosch relay kit that came with the 5-pin SPDT relay and the socket with pigtail harness but I don't know if that is still the case.
 
I plan on using weather pak type sockets and on going with a gel battery or lithium ion type if i have the coin when i am ready for it. The relays and fuses will be mounted inside a weather resistant project box that will be bolted upside down to the battery tray. They will be mounted to the inside of the lid which will be hinged at one end, and have 1/4 turn fasteners to open it to access the relays and fuses. The buss bar will be inside the box as well. The only thing that will be exposed will be the wiring going in and out of the box. Everything will be neatly hidden from view.

Mr Crackedback PMed me the tyco and bosch relay PNs. I checked evilbay and found these PN genuine bosch and tyco relays for about $7 to $11 each. Pretty inexpensive IMHO
 
crackedback said:
Good approach with the box.
Click to expand...

Thank you. I figure if a use a weather resistant project box upside down attached to the bottom of the battery tray then i can hide all this for a clean install. I will run my batt hot in the stock wire loom with the other wires between the battery and fenderwell. The headlamp wires that will go to the relays, and the batt hot will all come down the inner fender between the front of the battery and the radiator support. Wrapping them all in factory type vinyl wrap tape. Keeping it all stock appearing.
 
What size fuses should i hook it all up with. Should high beam be a different fuse than low beam? Can i assume use a 12 gage or a 10 gage wire from the battery to the relays? How about a fusible link?

Also since my relays will be in a sealed box i am looking at the non weather resistant ceramic 5 pin relay plugs. Not sure if theres a heat issue or not, or if regular plastic 5 pin plugs will suffice. Any recommendations?? Yes? No?
 
Connectors I used at the headlights are rubber booted, 90 degree, low profile, ceramic. This is for 7 inch round aftermarket fixtures with H4 bulbs. Expensive change there since the connectors came with undersize wire of wrong colors. I found new quality terminals that would accept my 12 awg.
Connctors at my relays are plastic. Wire line in out is 12 awg. Fuses for line in out are 20 amp. Wiring to relay coil is factory ( 18 awg I think ). Fuses to relay coil are 10 amp. These 2 fuses are inside the car, inline between headlight switch and dimmer switch.
 
So just run a 12 ga hot lead in from the batt to a buss bar? Would you recommend a fusible link?
 
I have a maxifuse inline before branches to relays. Only relays there today are 2 for lights and the horn. Fusible link would have worked too.
 
RedFish said:
I have a maxifuse inline before branches to relays. Only relays there today are 2 for lights and the horn. Fusible link would have worked too.
Click to expand...

What is the rating of uour maxifuse?
If i run 12 ga wire, for the feed, i will need a 16 ga fusible link.
 
How about trip resettable circuit breakers like in marine applications. Water resistant, and resettable? Any thoughts on this. Will be easier for me to panel mount these than ato/atc blade fuses.
 
There is an auto reset circuit breaker inside the headlight switch, why not use something similar for the power feed to the new relays? A fusible link would be a pain to replace out along side the road especially at night.
 
How about this box its a bit large for what i need. I only need 2 relays nice option for someone though.

Screenshot_2017-06-25-16-02-29.png
 
moparmat2000 said:
How about trip resettable circuit breakers like in marine applications.
Click to expand...

This is what I have instead of fusable link and powering my electric cooling, and then blade fuses and relays from there on,
I have 4 relays for headlights (one for each bulb element) so I will never loose both lights if I loose a relay.
They are also soldered direct and not using a pigtail socket.
I still use pigtail sockets right at the bulbs though, but with much larger wires.

Also, like Del mentioned I grab my relays out of Honda cars.
Pisses people at Walmart off, but...):D
Just kidding.
I have a stash of extras from the pick a part.
 
TrailBeast said:
This is what I have instead of fusable link and powering my electric cooling, and then blade fuses and relays from there on,
I have 4 relays for headlights (one for each bulb element) so I will never loose both lights if I loose a relay.
They are also soldered direct and not using a pigtail socket.
I still use pigtail sockets right at the bulbs though, but with much larger wires.

Also, like Del mentioned I grab my relays out of Honda cars.
Pisses people at Walmart off, but...):D
Just kidding.
I have a stash of extras from the pick a part.
Click to expand...
I am looking at bosch 20/30A five pin relays now, and if i do this as 4 seperate relays, that box i found on evilbay should be about perfect. What are you using size wise for blade fuses? I just bought a pair of GE H6024NH halogen sealed beams. I assume 50w/65w
 
moparmat2000 said:
I am looking at bosch 20/30A five pin relays now, and if i do this as 4 seperate relays, that box i found on evilbay should be about perfect. What are you using size wise for blade fuses? I just bought a pair of GE H6024NH halogen sealed beams. I assume 50w/65w
Click to expand...

The headlights are direct off the battery through the relays and not fused but the rest of the car is on the self resetting breakers.
I ran the 10 ga wire for headlight power through vacuum tubing for insulation insurance for it's route along the underside of the lip on the radiator support where the OE metal tabs for the old wires are.
I used a 30 amp breaker for the main cabin power instead of a fusable link.

My electric cooling is also direct off the battery through a 20 amp inline blade fuse using a relay that the thermostat for the fan controls, so there isn't much load on the thermostat switch.
Everything inside the car is pretty much original glass fuses and the factory fuse box, and almost everything in the way of lighting except for my headlights are LED so there is very little load anywhere.
My wipers, heater blower, headlights nor signals slow or dim at idle.
 
Meh. overkill. You don't have two headlight switches, two dimmer switches, etc. Just use two relays. You can get small mountable sockets for the bosh relays like the ones Crackedback sells on here

If "one beam" dies you still likely have the opposite to get stopped or slow down, etc
 
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