Ultimate Headlight upgrade: DOT Legal LED Headlamps!

[Ben's Z]

I am going to try to go out on a desolate road for some pictures with my Cibies tonight. Finding an unlit road in suburban Houston though may prove to be difficult.

[silvey19k]

well the hmvv only sits as high as a ranger maby lower but light is no problem. its not to tight of a beam and not to wide i use them all the time. they are however really noticeable and brighter than h4. but i would like to see some pictures befor i grab a pair for my z. just to see what they look like if it is to much ill just leav mine alone.

[Walter Moore]

Arne,

Do they still sell/use those bubble type headlight aiming tools? At one time all headlamps sold in the U.S. had three points cast into the lens for the vertical aiming tool. Mostly those didn't do much except keep oncoming traffic from being blinded by your low beams.

[Arne]

Those aiming tools mostly went away with the death of the sealed beam. DOT approved lights still came with the three nubs well into the '90s if not later. But I haven't seen one of those in years, and they won't work on lamps that lack the nubs.

[FastWoman]

I go back and forth on the LEDs. This year LED Christmas lights made their big splash in my neighborhood, and the older tungsten lights had mostly died during previous years. It just wasn't the same. The LEDs were cold and unsatisfying. To me there's something magical about a hot, glowing filament that we will miss someday.

However as a spotlight on our sailboat.... That's entirely a different issue!

[H4LIGHTS]

I've been told by others in the lighting business that these Truck-Lite LED's are popular with the logging trucks in the Pacific Northwest of the US. The drivers like them because they do not fail completely if a few LED's get damages or just stop lighting. They leave them on all the time while driving, day or night.

I'm sure that can be quite an advantage on dimly lit winding mountain roads.

It would be great to see an aerial view of the coverage pattern to compare it to other offerings especially in an S30 and an S130.

FWIW: I've attached an older beam pattern chart that is informative IMO.

(Low/Left Hand Drive and High beam shown are for an H4 E marked application)

Edited May 24, 2011 by H4LIGHTS
Chart Clarification

[Ben's Z]

Circa 1979 Cibies on LOW BEAM Will try follow up with LED's on Thursday night or sometime during the weekend. Stay tuned!

[Ben's Z]

Well bad news. It took some time and my wifes uncle who is an electrical engineer, but according to him using a volt meter, when you pull the hi beam switch on my car it reverses polarity. The voltage gauge would go from around 11 + volts then pulling the hi beam switch back to 11- Volts, and visa versa; thus my LED headlamps would only work on either a) lowbeam or hi beam. He thought this could be rectified with some sort of relay. Can anyone else confirm this? He said halogen bulbs don't care about a positive and negative side but he said with the diode on LED lamps it does matter.

[5thhorsemann]

search the relay circut herein, that will solve your polarity and voltage issues.

[SteveJ]

Switching polarity? Nope. They don't. The stock wiring on the 280Z has the 12VDC going to both headlights. The return wires go to the high/low beam switch. That switch selects the path to ground. Look at the circuit that Daniel Stern uses to demonstrate the value of relays. Note that the ground is common and you have two 12VDC sources coming in.

If your LED headlights require a common ground, you could put in relays that utilize a common ground. If you don't understand what I'm saying, let me know, and I'll draw up the circuit for you.

[Ben's Z]

What he said has to be true because the cibie high and low beams worked fine. I plugged in the first LED lamp that night compared it to the stock cibie. When the left front headlamps was LED it was on high beam and the right side was on low when the switch was on low beam. Pull the highbeam switch back and it would go off.

Switching polarity? Nope. They don't. The stock wiring on the 280Z has the 12VDC going to both headlights. The return wires go to the high/low beam switch. That switch selects the path to ground. Look at the circuit that Daniel Stern uses to demonstrate the value of relays. Note that the ground is common and you have two 12VDC sources coming in.

If your LED headlights require a common ground, you could put in relays that utilize a common ground. If you don't understand what I'm saying, let me know, and I'll draw up the circuit for you.

[SteveJ]

What he said has to be true because the cibie high and low beams worked fine. I plugged in the first LED lamp that night compared it to the stock cibie. When the left front headlamps was LED it was on high beam and the right side was on low when the switch was on low beam. Pull the highbeam switch back and it would go off.

I have studied the wiring diagrams from many of the FSMs' date=' especially after others pointed out to me that the 70 & 71 240Zs have their headlight circuits wired differently than other S30s. I have converted both of my cars to relays for headlight controls. I do know what I'm talking about, and yes, I am an electrical engineer.

I'll step you through the circuit, using a positive to negative convention.

1. 12VDC+ comes into the combo switch on the right using a White/Red wire.

2. When the headlight switch is in position 2, it completes the contact and goes out the Red wire. (See the first attachment.)

3. The red wire goes into the fusebox and goes through two fuses. The fuse for the right headlight has a Red wire. The fuse for the left headlight has a Red/Yellow wire. (See the second attachment.)

4. The Red and Red/Yellow wires travel to their respective headlights and land on the common pin for the headlights. Two wires come out of each headlight. One wire is Red/Black. The other wire is Red/White. The two Red/Black wires join as do the two Red/White wires. (See the third attachment.) The wires then go back to the combo switch on the turn stalk.

5. If the switch is in the low beam setting, the Red/Black wire will be connected to ground via the Black wire. If the switch is in the high beam setting, the Red/White wire will be connected to ground via the Black wire. (See the first attachment.)

At no time does the polarity change. The path to ground changes.

Since the D in LED stands for diode, yes, polarity is important. Did the headlights come with instructions? Look for any guidance on wiring. My guess is that the common pin is supposed to be grounded, as I said before.

If you still don't believe me, take the voltage readings at the headlights again. However, take out BOTH headlights. With the switch in low beams, you will find that you have 12VDC (probably less) between two of the three pins. When you change it to high beams, the pin that was positive before will still be positive. The negative will go to the third pin.