Methinks I could use a new 521 turn signal assembly...

[hessianben]

I've been chasing wiring grems for weeks now, and I've got it most of the way licked...

...except for the turn signals and brights!

 

I just finished upgrading (and deleting the old) headlight relay via Beebani's writeup;

 

Originally Posted by Drummerboy4as View Post

 

Get some wire, 12ga should work, get 2 in-line fuses (20-30amp), 2 40amp relays, and a few misc connectors.

 

Wire the 2 in-line fuses to the + post on your starter or battery, run those wires to the #30 terminal on your relays

 

For the low beam relay plug the red/black into terminal #87, run a ground to #85, and split the red wire that's plugged into your old relay plugging one lead into the #86 terminal

 

For the high beam relay plug the red/white wire into terminal #87, red/yellow into #85, the other half of your red wire goes to #86

 

The red, red/yellow, red/black, and red/white should be the four wires that are plugged into your old relay, you may need to extend them.

 

anyhow, this all went really smooth, and now i have lights again. (bright ones!)

however, the brights are always on now, and I have no turn signals.

I traced it back to the turn signal assembly on the column- The brights will turn off if I loosen the assembly and wiggle it around a bit.

makes me think it's not grounding properly...

The whole unit is pretty ragged and corroded...

 

 

If anyone has a spare 521 turn signal assembly around, please let me know!!

if you're in SoCal, I'll drive to you.

thanks!!!

[banzai510(hainz)]

I never thought the 521 set up was bad switchable power. However I noticed it is different that the 510 being a switchable ground

 

why them made them different I dont know.

 

I always thought it was EZ to install a H4 harness than do babanni's swap. just use the orginal as a low current trigger.

 

 

rember the highbeam switch on the steering whel put a ground on the circut and assume it goes to the stock relay

 

as for the turnsigs I never had proplem and dont know. but you will!!!!!!

[DanielC]

You might try to squirt some WD-40 into the switch and see if you can at least get some of the 40 year build up of gunk to move away from the switch contacts.

If I remember my 521 wiring correctly, I believe it works like this.

The 521 headlights use switched power. The lights are grounded. When you pull the light switch all the way out, power goes to the headlight relay, and through the NC (normally closed) contacts, to the low beam headlights. Power is also applied to the coil inside the relay, but the coil is not grounded.

When you switch to high beam, the turn signal switch grounds the headlight relay coil, and power then goes out the NO (normally open) contacts to the high beam headlights.

I reread your post. Because your high beams are on, until you unbolt the turn signal switch, you have a short somewhere that is making the original factory headlight relay stay switched to the normally open contacts.

Edited November 2, 2009 by DanielC

[hessianben]

If I remember my 521 wiring correctly, I believe it works like this.

The 521 headlights use switched power. The lights are grounded. When you pull the light switch all the way out, power goes to the headlight relay, and through the NC (normally closed) contacts, to the low beam headlights. Power is also applied to the coil inside the relay, but the coil is not grounded.

When you switch to high beam, the turn signal switch grounds the headlight relay coil, and power then goes out the NO (normally open) contacts to the high beam headlights.

I reread your post. Because your high beams are on, until you unbolt the turn signal switch, you have a short somewhere that is making the original factory headlight relay stay switched to the normally open contacts.

 

So you're saying that I've got a short that causes the high beams to be activated all the time, and when i ground the turn signal, it causes them to shut off?

 

Curious, can you see any faulty logic in the wiring steps I quoted in my first post?

[DanielC]

Perhaps I did not make myself clear. I will try to explain it another way. Not your fault, mine. I am going to be basic, (I hope) do not take this as a put down, I want to help you.

A relay is just an electrically operated switch. Apply a small current to the coil of a relay, and it can switch a large current. Your starter has a relay in it, only in a starter we call it a solenoid, because the relay coil also moves something mechanical, and engages the starter pinion into the flywheel. Afler it has done that, the starter solenoid closes some contacts, and connects your battery to the starter, and your engine cranks. This is a relay that just makes a connection.

 

A lot of relays can also switch connections.

The stock Datsun 521 pickup headlight relay does this. Go look at your headlight relay, or if you remember it has four wires going to it. Three of the wires are fat, one is skinny. If you unplug the skinny wire only, your headlights should turn on when you pull the tight switch all the way out. The low beam headlights should be on, but it is possible the low beam and high beam headlights got switched, and your high beam lights come on.

 

All the dimmer switch on the turn signal switch does is it grounds the skinny wire, that you unplugged from the original headlight relay. It shorts it to ground. But it is not a short, normally, until you move the turn signal switch away from you. If this wire actually does short to ground, the headlight relay thinks you are just driving around with the turn signal switch pushed away from you.

 

The following will work on a Datsun 521. It may not work with other Datsuns.

If your stock four pin Datsun headlight relay is bad, you can replace it with a modern "Bosch"cube type relay. Power goes to pin 30, and 86. The skinny wire goes to pin 85. Low beam headlights go to pin 87A and high beam headlights go to pin 87.

 

A quick review. If you unplug the skinny wire from your stock factory headlight relay, and turn on the lights, the low beams should come on. If you plug this wire back on the relay, and your high beams turn on, in spite of what you do with the dimmer switch, except unbolting it from the steering column, the switch is bad, and if the high beams stay on even when you unbolt the turn signal from the steering column, the skinny wire from the relay actually has a short.

 

The logic in your rewiring and adding a relay looks good. Think of it this way. Instead of the original headlight switch and relay being connected to the headlight bulb, it is now connected to another relay coil. The contacts on this new relay directly connect the battery to the headlights. This takes all the headlight current out of your 40 year old original fuse block. If also avoids taking electricity from your battery, running it through an old fuse block, through a connector behind your glovebox, over to the light switch, back through another connector, also behind your glovebox, out to the headlight relay, and finally, to the lights. If you are upgrading your headlights, make sure your grounds are good, also. If I remember right, the black wire for the headlight ground goes to an eye that is screwed down to one of the mounting bolts for the voltage regulator.

[slodat]

DanielC - that is an excellent, patient explanation! Nice work!

[hessianben]

Thanks Daniel,

appreciate you taking the time.

I unplugged the thinner wire that goes to the dimmer switch, and

the low beams still work. High beams come on when i plug it back in regardless of the switch position.

I may wire a jumper from the relay to the switch, just to make sure it's the switch and not the wire.

sounding like the switch is faulty though...

 

looking for a donor truck if anyone has a spare switch!

[DanielC]

The thin wire off the relay, should be the same color at the turn signal switch. I cannot remember if there is one plug at the turn signal, or if there are individual plugs for each wire. Take the turn signal switch off the steering column, and try to clean it, spray it with WD-40, whatever. You would be surprised what you can take apart and repair if you are careful.

[hessianben]

The thin wire off the relay, should be the same color at the turn signal switch. I cannot remember if there is one plug at the turn signal, or if there are individual plugs for each wire. Take the turn signal switch off the steering column, and try to clean it, spray it with WD-40, whatever. You would be surprised what you can take apart and repair if you are careful.

 

I had to do some investigative tracing for that wire.... it's black/red at the switch, but somewhere along the line it becomes light green/yellow.... random.

I'm working on sourcing another switch, but until then I'll be fiddling with the stock switch.

Thanks again everyone for the help!

[DanielC]

Now that you know how the headlights work, all you need to do until you get a working dimmer/turn signal switch is this. Get a simple toggle switch, and mount it within easy reach. Ground one side of the toggle switch, you could probably use one of the screws that mount the switch for a ground. Run a wire from the other side of the switch to the terminal on the original headlight relay, that has the skinny wire on it.

Switch on, high beams, switch off, low beams.