70 headlight help, needed please

[milehiroadster]

I've been a member for a while, but have never posted for help before. I do
use the site quite a bit for research. I've owned a 66 1600 for almost 45
years, but just last year acquired a 69 & a 70 2000, both non-running, one
for about 5 years, the other for about 35 - 40 years! (I've also got a
couple of parts cars & a fair bit of spares) I retired last year and am now
in the process of "restoring" all three, probably selling the 1600 & one of
the 2000's and then keeping one 2000 for my self.

I was driving the 70 2000 a few weeks ago and as it started to get dark, I switched on the lights. No headlights at all, not low or hi beams on both headlights. All other lights are fine. No blown fuses. I've swapped in another light switch and another headlight relay and still have the same problem. Ground appears good. The relay sounds like it's working when I pull the light switch stalk all the way out. The indicator light for the high beams, on the speedometer is on, moving the turn signal stalk forward and back gives the light a small blip, but the headlights do not come on and the indicator light stays on in either position.

Anyone have any ideas? Has anyone seen this before?

[fj20spl311]

I would first check the headlamp bulbs. There is a very good wiring diagram in the wiki. 69 and 70 headlights use the ground side to control the lights, the all red wire should be hot directly from the fuse. if its hot, then try grounding the other two wires at the connector in the wheel well

[redroadster]

Try switching it on ( by someone else operating the swt.)in the dark & you look for arcing from a connection , I put a lighter draw component in place of the heavy Draw headlite and see if that works normal where you have copper tarnished wiring to brass connectors that's big resistance I solder with acid solder to improve connection there & wash off

[david premo]

Last I checked rosin core solder is the preferred solder for electrical work.

[redroadster]

Last I checked rosin core solder is the preferred solder for electrical work.

Yes but try it on tarnished wires to brass ( 4 decades) Useless,

[Curtis]

Last I checked rosin core solder is the preferred solder for electrical work.

Yes but try it on tarnished wires to brass ( 4 decades) Useless,

I've never had a problem with tarnished wires. Sometimes I run some steel wool over them.

[Curtis]

Per your email request here is some advice. I take it you've looked at this.

https://kendo-usa.org/datsun/datsun_hea ... _69_70.pdf

I personally hate the 69-70 headlight layout. The always hot headlights seem like a short looking for a place to happen.

First thing is to determine if you have 12v at the headlights. Unplug the harness from the headlights at the sidewall where hooks up. Use a voltmeter to see if you have voltage there in the engine harness. You'll need to do both sides. One has a red wire and the other red with a blue marker. There is a fuse for each. If that is good then go to the relay.

Unplug the relay. Hook a ground wire from the red/white wire if on high or red/black for low from the harness plug. If you get headlights then the problem is probably the relay, switch, or ground to the frame which is attached to the frame below the washer tank. I believe the ground wire connection is in the 4 pin plug inside at the firewall that connects dash and engine harness. Something else to check.

BTW, the 69-70 fuse box is known to have a problem with loose rivets and burning because of it.

[Curtis]

And this.

https://kendo-usa.org/datsun/6970%20fusebox.pdf

[redroadster]

Pos is the back side of the electric power, neg the before the component side . Don't believe that ?
Display the ign coil wiring with points condenser then explain how that works
You don't understand what I'm talking of soldering the multiple spades to old copper wiring , but then who here uses a ohm meter to test ,you can just cut out the multi plug and joint the wires .
Which takes the moisture out of the wire forever

[Curtis]

I suggest you look at the drawing to see how 69-70 headlights are wired. Ohms to test volts? I use a multimeter regularly. But what do I know, I just build this wiring.

[milehiroadster]

Got the headlights back working. Thanks for all the replies, especially to Curtis who nudged me in the right direction. I did not have 12v at the red & red/blue connections at the the harnesses from the headlights at the sidewall where they hook up. I then checked for continuity from the fuse block to those two headlight connections and I was originally getting some strange results, but then realized the high beam indicator bulb was allowing current to leak back and change the readings. Once I removed the indicator bulb I discovered no 12v at either headlight connector and no continuity to the fuse box so I started tracing things back and discovered the six-pin connector from the under dash harness to the engine harness had become disconnected. Problem solved! I guess I should have looked for that originally, but because of the weird way the lighting circuit is wired, the symptoms where deceptive.

[Curtis]

Great. 69-70 headlights are a PITA with the always hot headlights and grounding through the switch. Really a problem if you put in a 68 switch by mistake. And the unique headlight relay. I figured out and probably someone else on here before me how to use a couple 5 pin relay. Or was it one relay?