PIAA 's connected to Headlights (1 Viewer)

[aktundra]

When I bought my '80, the PO had installed a large pair of PIAA's. The switching on the dash always seemed akward to me. One 3-way toggle (only one direction was used) to turn the lights on. then another 3-way toggle to switch from high beams to low beams (the center position was not used).

Just seemed like a lot of unecessary switching and a bit of a handful to be driving when switching back & forth between high & low beams.

I wanted the shop to change things around so that I turned on one switch to activate the circit (turn the lights on), then switch back & forth between high & low with the headlights (via the factory headlight switch).

I received the following from PIAA Support:

NOTE: this harness is designed for a vehicle with a positvie (power) headlight switch. Vehicles with negative (ground) headlight switches (incl. some Toyota & Mitsubishi models) cannot use the headlight interconnect feature).

Based on the above, can I connect these lights to my headlight switch?

 

[Bearcat80]

The way I did it was to wire the ground for the relay to the ground of the high beams (80 series high beam lamps always have power and are switched by the ground) This way the PIAA are only on when the highs are on which is what is legal in Oregon unless the lights are covered. I leave the switch on so that the PIAAs come on when I turn on the high beams. You will have to do some voltmeter work to figger out which wire is which. There is some info on Slees site about doing this, of course the easy way would be to buy slee harnesses.

 

[aktundra]

To clarify, these PIAA's have both a high & low.

I am trying to find a solution that allows me to controll the hi/lo of the driving lights with the hi/lo of the headlights via the headlight swith.

 

[Bearcat80]

Hmmm, that may require more electrical skill than I have. I think you may have to use separate relays for the highs and lows, as the high beam would be ground switched and the low beam hot switched. Does the PIAA set up have two relays? if, so you are in good shape, if not you'll need to get another relay.

 

[haffi]

To do this you will need two relays. One of them needs to have five contacts. The drawing below shows how this can be done.

I recommend to buy two 5 pin relays because some 4 pin relays have different pin setup. But if you have two five pin you can use the drawing.

If wired like this you can turn the piaa´s on with when your tail lights are lit. But only with the lo-beams. Then when you turn on your original high-beams the piaa´s also switch to their high-beams.

This pic shows the number of the pins on the relay.

Good luck

 

[Bearcat80]

Aha! I knew I was missing something. Without the five pin relay, you would have to manually turn of the fogs.

 

[aktundra]

Gees I wish I understood electrical stuff . . . .

Haffi, is there a reason you called out a feed to the switch from the tail lights, for the PIAA low beam, and a feed from the high beam headlights, for the PIAA high? Could the feed to the switch come from the low beam head lights?

Second Q: There is a mysterious white box labeled "PIAA Professional Systems". It just has two pugs coming out the bottom. Any idea what this box may do? Does it likely contain relays? Would the solution you digramed replace this unit?

 

[96r50]

Could the feed to the switch come from the low beam head lights?

Yes.

 

[haffi]

Yes you can use lo-beam to feed the switch. The main reason that I recommend using the tail light is that it is easy to find inside the cabin.

The "PIAA Professional Systems" box contains relays, that will not be used if you connect the lights like the drawing.

 

[Bearcat80]

The other advantage to tying into the tail lamp(any back light bulb in the dash) circuit is that you can run the fogs without the low beams being on. This is critical in heavy snow or fog.

 

[BigO]

Negative switched headlights...

haffi,

I don't think that diagram will work. It calls for "power from high beam" and the 80 is negative switched. I think that means the power is always there at the headlight and the ground is switched. I don't have wiring diagrams for the 80, but I think that was mentioned earlier in the thread as being the reason that the original PIAA provided wiring harness will not work.

I made up the attached schematic, I think it's the same as what you've proposed but uses the negative switched headlight circuit.

I don't have the 80 series wiring diagram so I could be way off base...

 

[BigO]

relay basics

Also, here's a web page with some helpful relay info...
http://www.teamrocs.com/technical/pages/relay_basics.htm

 

[haffi]

I know that the lights are negative switched, but that means that the switch in the dashboard gives a negative feed to the headlamp and the dimmer relay. But the lights themselves are positive switched. Meaning that you can get positive high and low beam if you tap into the power behind the headlamps.

This is at least the way the lights work in my hdj81 and all other landcruisers I have seen and worked with. Both diesels and gassers.

On the other hand in the 2007 Hilux. Toyota has changed this system, in them you have 3 positive constant power wires into the headlamp. And then to turn the lights on, the headlamp and the dimmer relay turn one wire at a time to negative.

 

[BigO]

thanks

I know that the lights are negative switched, but that means that the switch in the dashboard gives a negative feed to the headlamp and the dimmer relay. But the lights themselves are positive switched. Meaning that you can get positive high and low beam if you tap into the power behind the headlamps.

This is at least the way the lights work in my hdj81 and all other landcruisers I have seen and worked with. Both diesels and gassers.

On the other hand in the 2007 Hilux. Toyota has changed this system, in them you have 3 positive constant power wires into the headlamp. And then to turn the lights on, the headlamp and the dimmer relay turn one wire at a time to negative.

Thanks, that clears up some confusion for me. I'm helping out with this, so I don't have wiring diagrams or even an 80 handy to go check ideas.

So there is a set of negative switched headlight and dimmer relays that then positive switch the actual bulbs.

Would it be practical to use those negative switched circuits if you're adding switches and working in the dash area anyway. It might be easier than running a wire from the main headlights back into the dash.

 

[haffi]

I would not recommend adding more stress on the original lightswitch, I have no idea of what the contact inside them are rated in amps.

If you use the positive power from the lights you are "stealing" power after the relay. Then you dont have to worry about adding a relay or two to the circuit.

You will always have to run wires trough the firewall, so one two wires dont matter do they?

 

[BigO]

Good points,

What is a typical relay pull-in current, I was thinking in the 100mA range but they could be much more depending on the relay. Sure don't want to over-stress the OEM switches...

I was thinking it might be better to avoid messing with the higher power headlight circuits coming back through the firewall, but you're right we'll need to pass through something at some point...

thanks...

 

[robmir]

If I guess right you got the PIAA 80 Pro Low / High lamps which are the same I have on my FZJ80. This lamps came with a H4 bulb rated at 90W/135W and optional with a heavy duty wiring harness the 100W/150W ceramic base bulbs.

They were available with 3 beam patterns: Fog, Standard high beam and Pencil high beam but the most popular were the Standard High Beam.

You should have a white box with a PIAA logo on the removable cover, which hide the relays.

It came with two switchs to be installed in the dash: one with two positions to select the high or the low beam and another with three positions to turn off the lamps in the center, low switch position to turn on all the time the lamps and in the upper position it would allow you to turn on the lamps together with the high beam.

Even as PIAA told you and is noted in the wiring diagram that came with the lamps, that they are designed to work only with positive signal you can modify the harness without any aditional relays to work with the FZJ80 negative switching as I did on mine.

The PIAA stock wiring harness relay box has a wire that should be connected to the ground: this wire is the one you will hook now to your stock high beam wire which provide a negative signal. The positive trigger signal wire of the PIAA relay box will be connected to the common pin of your stock high/low lamps which carry +12v only when you turn on your headlamps on.

I have this setup working fine for the last 10 years, allowing me (when I am driving off-road) to turn on at the same time the high side of my stock low/high headlamps, the inner stock high beam lamps and the PIAA high beam which together could blind any oncoming driver if you are not carefull. The PIAA low beam are very good to fill the areas not covered by the stock low beam specially when it´s raining since they go lower and wider than the stocks.

I replaced the stock PIAA toggle switchs which are quite ugly with square rocker switchs I bought on a marine shop which have the same size as the stock used by Toyota. You will need one with two positions and one with three positions.

The PIAA 80 PRO halogen series lamps still have the best optic reflectors till date, better than any IPF, Cibie or any other top brand.

Of course there are more advanced low beam proyection lamps using xenon high voltage discharge bulbs in the market but none of them has reached a solid and powerfull instant high beam.

 

[Brian894X4]

I know that the lights are negative switched, but that means that the switch in the dashboard gives a negative feed to the headlamp and the dimmer relay. But the lights themselves are positive switched. Meaning that you can get positive high and low beam if you tap into the power behind the headlamps.
.

Actually, the high beams lights are negative switch at the lights too. At least on U.S. spec models. I ran into this same headache myself when trying to wire up a set of lights to come on with the high beams. What I did was just simply run a single relay that was switched off the negative High beam signal. It was more of a pain, but easy enough to wire up if you know relay basics.

The way they are wired up is that when you turn the low beams on, positive power is supplied to BOTH low and high beams. With the low beams already directly grounded, they turn on, but the high beam ground is switched, so it stay off, until the high beam switch is turned on and then the high beams come on as well. Which also means its not possible to run only high beams with this set up also.

I'm guessing the reason for this wiring set up is to allow them to cut off both high and low beams via a single main headlight relay, whether both are turned on or not, when the auto off feature is activated.

A couple points worth noting for the Toyota LC headlight system that is unique from other vehicles. There is a single headlight relay for all four headlights (maybe carrying a spare wouldn't be a bad idea?) There are two headlight fuses. One controls the left high/low beams and the other controls the right high/low beams. So, there are not seperate fuses for high or low, just the two different banks of headlights.

The high beam indicator is powered off of the right headlight fuse, but is negative switched just like the high beams themselve via the same circuit.

To power a set of lights via the high beam switch, this is what you can do....

A standard auto relay has four poles, a positve and negative to activate the relay and two poles to supply power or ground from one source to another. Simple wire up the positve pole to always have power or switched power from the ignition, then wire the negative pole off of the high beam negative switch. Connect the source pole on the relay to positive power, such as the battery or some other source that is capable of providing proper amps, then wire the other pole to your aftermarket light circuit, either powering it directly, or via a switch or powering the aftermarket light relay.

When the high beams come on, the new relay will activate and send positive power to your aftermarket light circuit.

That's what I did. My aftermarket lights are powered off a 3 position switch, with one position off, one position on with the high beams and one position on whenever the switch is turned on. I pretty much always just let them come on with the high beams.

Hope that helps.