(Help) Wiring offroad lights to high beams 100 series with DRL (Help)

[Madbodhi]

Trying to wire my Hella 4000's to my high beams only with no manual switches. I was under the impression that the DRL use the high beam bulb at only 6 volts. I tapped into the + wire off the high beams but my meter however shows 14.7 with the engine running both with headlight switch off (DRL position) and with high beams switched on. Any solutions to my dilemma that don't require adding a manual switch?

 

[Madbodhi]

I found a way to disable or add a switch to the daytime running lights over on Ih8mud. I may go this route unless a more elegant solution presents itself.

 

[Madbodhi]

Ok. Disabling Drl's at the relay doesn't help. After alot of looking at schematics and how the switching is done I went and tested the high beam fuse. Eureka! Despite the high beams being powered for Drl's the power does not ho through the 20a high beam fuse. It is powered only when high beams are switched on. Yay, easy peasy to install an add-a-fuse to provide the trigger.

 

[Madbodhi]

I take it back. That doesnt work either. I'm seriously stumped.

 

[DiploStrat]

Dead Easy!

I have done this for years. Use a relay.

1. Wire your driving lights, with the appropriate gauge of wire, to a good 12v source.

2. Depending on how your vehicle is wired put an appropriately sized relay in either the positive or negative side of the circuit.

3. Wire the control side of the relay to your high beams, again, positive or negative, depending on how your vehicle is set up.

When you hit the high beams, the driving lights come on. Low beams, they are off.

Notes:

-- I have always wired this on the positive side, but some modern vehicles switch the negative side. Either one will work.

-- A dash switch will allow you to shut off the driving lights whenever you wish, as when you have covers fitted, during inspections, etc.

-- A tell tale on the dash switch is a nice feature.

Dead easy, hit your high beams and everything comes on, dim your lights and everything shuts off.

 

[Madbodhi]

Know how I know you didn't read

 

[4Beast]

Know how I know you didn't read

I can't tell if you are joking, or just bashed a guy who was helping you...

 

[DiploStrat]

Again, dead easy.

Trying to wire my Hella 4000's to my high beams only with no manual switches.

Got it. Use a relay.

... I tapped into the + wire off the high beams but my meter however shows 14.7 with the engine running both with headlight switch off (DRL position) and with high beams switched on.

Did you notice the comment about switching the negative side?

Any solutions to my dilemma that don't require adding a manual switch?

Yes. Use a relay. And, by the way, your own testing has shown that your vehicle switches the negative side.

Take these answers to any competent auto electrical shop and they will fix you right up. The REAL issue is what kind of driving/off road light. In the old daze, we used airplane landing lights and needed huge wires and relays. Now, with LED lights, the amp draw is trivial, so you can use lighter wire and a smaller relay.

Does this make sense to you? N.B. This diagram shows negatively switched headlights and positively switched driving lights. You could switch the driving lights on the negative side as well, but generally it is not worth the effort. (Most vehicles use negative switching so that the computer can tell if a light burns out.

 

[Madbodhi]

Not trying to be a jerk, just frustrated. I am using a relay and I knew that it was a negative switched system. I tried getting the trigger signal off the positive headlight lead because I'd been led to believe that with the Daytime Running Lights on it carried only 6 volts which I'd hoped would be below the threshold to trigger the relay. The fact that the Daytime Running Lights are on means its a completed circuit so tapping the negative for the trigger wouldn't work as the relay for the Hella's would be triggered anytime the Daytime Running Lights are on and not just when the High beams are switched on. I tested the DRL relays trying to find a positive or ground I could use but no joy. I have searched several sites and have yet to find a definitive answer. I clipped the A3 wire on the DRL relay to disable the DRL and they are currently not lighting up while all other functions are unaffected. Tommorow I'll test and see if with the DRL's disabled I can run a negative trigger off the highbeams to the relay. I'm cautiously optimistic. I did find one guy who says he ran the trigger off of the A5 terminal on the DRL relay and added a direct to ground wire off of A3. However,despite being posted in 2012 with responses up to Nov of 2016 not a single other person has verified this method. If I cant get them working tomorrow I will admit defeat and put the Hella's on a switch...at least until I get my hands on a factory service manual electrical wiring diagram.

 

[DiploStrat]

Still Not That Hard

Not trying to be a jerk, just frustrated. ...at least until I get my hands on a factory service manual electrical wiring diagram.

Not accusing you of being a jerk and the last part of your post is the key - you need the manual.

I no longer have a Land Cruiser and never looked at the electrics when I did. That said (I know, this is where it gets dangerous as I don't have hand on experience with your vehicle), consider these ideas:

-- Ignore the DRL for the moment, you are looking for an electrical circuit that is completed only when the high beams are on.

-- The engineers who designed all of this were lazy and chose the easiest possible way to do things. You want to do the same.

-- A normal headlight has two filaments, high and low beams, which are switched various ways to create high and low beams. That is, either one may be on, or they may both be on for high beams. Same idea if there are four headlights. Are you are sure that that there is only one positive lead to the headlights? Normally there would be two, one for low beams and one for high. But, in any case, it doesn't matter.

-- If you have a negative switched circuit, then any and all positive leads to the headlight(s) will show 12v when tested to ground. You just need to find the ground (or negative) leads. There should be two - one that completes to turn the low beams on and one for high beams. (As an aside, if you are correct that your vehicle achieves DRL by dropping the voltage, then I would suspect that there might be a third ground return that has a resistor in it, but this is pure speculation.)

Basically, on a negatively switched vehicle there is a 12v lead(s) to the headlights and this circuit is always live. Somewhere out there there is a negative (or ground) lead that is switched. This is the one you want. Doesn't matter whether you tap in at a fuse box or simply splice into the wire itself as long as the return from your relay is before the switch.

So, it may be easier for you to trace circuits out at the headlights themselves, rather than at the fuse/relay box. (In the old days, with a positive switched circuit, I simply pulled the connector off of the headlight, wrapped my relay trigger wire around the lead to the high beam, and then put the connector back on - simple, water protected, etc.

Parthian Shot: Remember, you are going to run a constant 12v to your relay, it is the ground that you are interrupting. (See the diagram.)

Hope some of this helps. Good luck!

 

[Madbodhi]

Back at it today. Even with the A3 wire clipped and the Daytime Running Lights not turning on there is no + or - lead from the headlights that is live only when highbeams are switched on. I can however now verify that the method I mentioned earlier does in fact work. Cutting the A3 wire on the DRL relay located next to the airbox ,(black and white wire but be careful,there are 2) and running it from the relay directly to the very convenient fender mount ground right next to it. You can then get a + trigger feed off of the red and yellow wire in A5 that energizes only when high beams are turned on. Additionally your Daytime Running Lights still work.


The 2 wires that make the magic happen. If I'd known that this would work I would have clipped the A3 wire (pink connector) further down. Then I could have had enough wire to simply add a ring terminal for the ground rather than an extra connector. The A5 wire is right next to it(red heatshrink).


SUCCESS!!!!!

 

[DiploStrat]

Congrats, but do note that you are now switching on the positive, not negative side.

But if if works, go for it. That is all that matters.