Some Complex Relay Harness Schematics (my contribution)

I am going to post some schematics that I have made for random people. I figured I would contribute them here; because as I stated in another thread I no longer have my Explorer (RIP) but everyone on this forum was ALWAYS so helpful (including for my recent question) and I wanted to give back some to say thanks. These schematics are for positive switched systems, but I can adapt them to ground-switched systems if anyone needs me to do so. Also, they are shown for H4 bulbs, but quickly and easily can be adapted to work with ANY bulb as I have labeled what each pins function is.


This first one is one I designed for a user who had bixenon projectors AND a seperate halogen headlight (bixenon projector where the low beams used to be and the halogen high beam was left stock). This resulted in a problem, because everytime he flashed his high beams, it would flash the xenons as well (since they operated as his high beams TOO). This schematic SOLVES that. If the low beams are not on, it only flashes the halogen bulb, if the low beams ARE on it flashes/turns on both. It could be used in a variety of ways. i.e flashing auxillary lights or fog lights instead of the headlights during the day etc.



This NEXT schematic is an off-shoot of the above one. It is designed with a similar purpose, but instead of flashing BOTH at night, it ONLY turns on/flashes the bixenon high beam when the xenons are on. The halogen high beam only works when the xenons are off.




The next schematic I posted in another thread on here, it is a simple wiring upgrade harness schematic. It uses 9007 plugs in and out, but allows the user to run a higher gauge of wire, reducing voltage drop.



If anyone has any schematic requests, I can whip one up pretty quick to do a lot of different things. Just ask me and I'll see what I can come up with.

 

[Dannyboy]

nice designs, very clean.

I wouldn't mind seeing something for rear facing lights that
1) have a choice of being on/off with vehicle reverse lights
2) can be turned on independent of vehicle being in reverse

Also, if you have any experience with a relay that could leave a light on for 30-60 seconds after a vehicle is shut off (puddle lamps, fogs or headlamps) that would be cool as well.

 

[inh]

nice designs, very clean.

I wouldn't mind seeing something for rear facing lights that
1) have a choice of being on/off with vehicle reverse lights
2) can be turned on independent of vehicle being in reverse

Also, if you have any experience with a relay that could leave a light on for 30-60 seconds after a vehicle is shut off (puddle lamps, fogs or headlamps) that would be cool as well.

Cool ideas =] I planned on whipping up a schematic for the reverse lights exactly like you described for when I do mine.

 

[PedroDaGr8]

I'll see what I can whip up for you. The delayed turn off can be accomplished a few ways, some common ones are the use of capacitors or delayed turn off relays.

Are those the only two states you want for the reverse lights or would you like an off at all times state as well?

 

[PedroDaGr8]

Here ya go.

AN explanation of the wires coming out of the switch:
The green wire is the circuit that turns the reverse lights on with the switch
The orange wire powers the switch, so if you want the lights to only come on with the engine, then find an ACC line. IF you want them to be able to come on even when the engine is OFF, find an always on line.
The blue wire is the circuit that turns the lights on when the reverse lights come on.

An explanation of the other wires in the circuits:
The red wire is the power from the battery to the lights.
The black wire is of course the ground wires. These can be grounded as usual.
The purple wire is the "signal" for the reverse lights. You can simply tap one of the reverse light wires for this wire.

The diodes are there to prevent any weird back flow of current.


The switch used is a SPDT (Single Pole Dual Throw Switch). If you want the ability to turn them off, you need an On-Off-On SPDT switch. You can find lit and unlit versions of these switches.

 

[Dannyboy]

Nice!

 

[PedroDaGr8]

Awesome, glad you like it. It was pretty easy to make.

The diodes are not 100% necessary, but I just don't like the idea of there being the possibility of even a bit of reverse current flow into something that you touch. Also, if you start getting the pop when the relay shuts off (similar to what another member had) I saw something about adding a supression diode on the relays. This is supposed to disipate the charge created by the collapse of the coils magnetic field. I have a feeling THAT is what causes the pop.

Once again if anyone else whats a schematic made, holler at me.

 

[PedroDaGr8]

By the way dannyboy, I came across a circuit schematic for the application you wanted (the adjustable delayed turn off of puddle lights etc.)

http://www.the12volt.com/installbay/forum_posts.asp~TID~111646~KW~delay+turn+off+relay~PN~0~TPN~2

It uses a BS170 mosfet (that is the thing labeled Q1 BS170) with the pins being:
Pin 1 - Drain
Pin 2 - Gate
Pin 3 - Source

The best thing is, that mosfet is like 25 cents + shipping.

SO that parts I see are:
47uF capacitor found at RadioShack for $1.39

BS170 Mosfet found at Fairchild Semiconductor for $0.25 (according to the internet an alternative is available from radioshack, it is called the IRF510 found here for $1.99)

Three 14N001 Diodes found at Radioshack $1 each, so $3 total (one for the relay as well)

1M Ohm Potentiometer found at Radioshack for $3

30/40A Relay + Socket - $5-11

So in parts you have a cost of $13-$18 (plus the wires and breadboard if you decide to use it), to make a relay that turns on and then delays turn off for an adjustable amount of time. By turning the pot you can adjust delay length and you are good to go.


I am going to reproduce that schematic for here if I can. Watch back here for the reproduced schematic.

 

[PedroDaGr8]

Here it is. The lights on signal comes via the orange wire (so you turn on the lights and that wire gets 12V). The 12V on that line stops, it keeps providing current to the lights for a set amount of time (which can be varied via the 1M Ohm Potentiometer).

This means, you can turn your lights on and after you turn the switch off then they will stay on for another 30 sec or whatever amount of time you set it.

 

[Dannyboy]

Pedro, I'm impressed sir, not let's see if I can ask this question properly, a while back I had a guy help me wire up some driving lights and he did this in a manner that required less wires. It was a few years back and I've never found anything similar, but wondered if there was an advantage/disadvantage of doing it this way.

He looped 2 positions on the relay and instead of it being a positive relay, it was a negative relay. Hitting the switch "on" completed the negative circuit I believe.

Does that make any sense?

 

[PedroDaGr8]

The negative relay part makes sense, you just put the relay on the ground side instead of the battery side, its called ground-switching (very common on Japanese cars). The looping part doesn't. I have designed circuits using loops before, but never saw that cause a delayed turn off (I have used loops to make the relay sort of a LATCHING relay, but that is a seperate thing than a delayed turn off). If you had any pictures, that would be AWESOME because I could likely figure it out from a picture.

 

[Dannyboy]

no it had nothing to do with delay, but it was something like
30-switch
85&87- connected with jump wire
or
86&85-connected with jump wire

remaining wire- to lamps

 

[inh]

I like that delay off relay setup. Would be sweet to use on rock lights at night. Much cooler and probably better than 'puddle lamps'

 

[PedroDaGr8]

no it had nothing to do with delay, but it was something like
30-switch
85&87- connected with jump wire
or
86&85-connected with jump wire

remaining wire- to lamps

Weird, I can find a working setup, but to be honest, the relay becomes USELESS. It serves no real purpose. The switch takes full strength charge, which invalidates the point of having a relay. The point of a relay is to allow a switch to have a low amount of current running through it, with the relay having the high current.

Very very odd.

 

[inh]

He probably looped pin 30, which was also connected to +12v, and pin 85 or 86, one of the coil pins, and then you just have to ground the coil. I like using a setup like this, because then wherever your switch is you just have to run one wire to it from the relay, and then ground the other pin on the switch, which is easy enough to do. Also, if your wire from your switch to your relay were ever to get cut or frayed on the chassis, it would just ground, completing the circuit, instead of it carrying +12v and shorting out

 

[PedroDaGr8]

Ahhh, I see. Use the same 12V for both sides, then just ground the switch. That makes sense, I would have broken it off before hand and split the line, but in fact it is the same thing. Duh. Sure feel dumb on that one.

Shouldn't be too hard to make the schematic I made ground switched as well. I'll try to make it tonight or tomorrow.

 

[PedroDaGr8]

New ground-switched version of the reverse lights schematic. This version has the added benefit of making the diodes unnecessary.

 

[inh]

Hey pedro, on the delay turn off diagram, the diode on the relay is the wrong direction. Installed like that the diode will let all the current flow through it to ground, and the relay probably wouldnt energize. You want the diode flipped around, so when the magnetic field collapses, it only lets positive electricity get to the positive side of the relay.

 

[PedroDaGr8]

Hey pedro, on the delay turn off diagram, the diode on the relay is the wrong direction. Installed like that the diode will let all the current flow through it to ground, and the relay probably wouldnt energize. You want the diode flipped around, so when the magnetic field collapses, it only lets positive electricity get to the positive side of the relay.

DOh, thanks for noticing that. I'll post a new schmatic with that corrected in a day or so.