Making a switchback circuit: yellow fogs to turn signals

Im thinking of something. Im going to get clear bumper turn signals for my 2000 Tacoma. Id like to have them wired up to a switch with yellow LEDs for fogs. Then im going to set up a relay and capacitor to link them to flash with the turn signals, which ill relocate to the parking lights. I could also use a p-channel transistor to save some space.

Looks like ill have to wire up something like this, im minus the diode between the turn signal and running light, just need to find the right capacitor:


So always yellow, but amber with turn signals. It would need two bulbs.

Unless i find a switchback LED that is yellow and amber, which would already have the transistor function built in.

All i have found are amber/white and amber/red switchback LEDs. Anyone have a source for yellow/amber?

If not ill just proceed and have yellow only in the lower lamps.

 

might be hard to source, most people identify amber and yellow as the same even though they are a little different.

sounds like a lot of work for not much change there.

have you considered just adding extra fog/driving lights like these: http://www.ebay.com/sch/i.html?_fro...hts.TRS0&_nkw=flush+mount+fog+lights&_sacat=0

make life much easier and none of the wiring hassle

 

Actually the master plan was to have clear lights all around. Yellow and/or amber in bumper, turn signals in parking lights, and these mounted on top of bumper.

http://www.ebay.com/itm/17186714099...m=&sspagename=ADME:X:eRTM:MOTORS:1123&vxp=mtr

 

Or im debating about doing a yellow lamin-x film over the turn signals to get the yellow effect. Then i could use the white/amber switchback to get the desired effect.

 

I put 1157 sockets in clear turn signals on mine. This allowed me to use amber/clear switchback bulbs. They are white when on with the parking lights, but flash amber.

 

I like it, just debating if your fogs with yellow laminx would look good. Cant seem to find any pics of it, might just photoshop it.

Let me ask, the floodlights behind the grill. what wattage are they and what gauge wire did you use for them? Did you wire directly to a switch or did you use a relay or transistor?

 

Those are hella 500s with 100W bulbs in them. They are wired through a relay with a switch. I don't remember the gauge wiring, but it came with some 150W KC daylighters that I used to have.

 

So ive found this is very doable with the right capacitor. Wiring one in parallel between pins 85 and 86 (or 86a) will hold the relay open for the extra second needed between flasher pulses.

The issue now if finding the right fraud capacitor to make this work. According to http://forum.allaboutcircuits.com/threads/can-a-capacitor-hold-open-a-relay.16210/, the formula to find this is:

t=-RC*ln(V/Vm)

R=coil resistance (930ohm if using a EFI relay)
C=capacitance of capacitor (?)
V=pull-out voltage (?, lets assume 12V, if someone has other info, please do tell)
Vm=initial voltage across the capacitor (12V, or what will be going across the relay coil)

so...

1=-930xCxln(12/12)

1
___ = -930xC
(ln1)

1
__
1
______ = -930
C

1
- ____ x -1 = -930 x -1
C

C = 930

Does this look right? I am concerned that there is info i dont know, such as the minimum pull-in and the drop-out voltage of a Denso or Bosch relay that we would find on our trucks.

What if pull out voltage is 9V?

1=-930xCxln(9/12)

1
_____ = -930xC
-0.288

1= 267.84xC

1
__ = 267.84
C

C= 1/268

Ehh, cant be right, its been too long since i took algebra.

It doesnt say what farad measurement applied but im assuming uf, as this seems to be most common. Smallest capacitors i found have been 16V, one of these of at least 930uf should work?

 

Other thing is that i have a bunch BMW relays which look like there is a capacitor already in parallel to the coil. I could use these, though i doubt they would have anywhere near the capacity to hold the relay open for a whole second. I would prefer to use a EFI relay, as i can wire it into the empty spots in the fuse box.