Headlamp Relay - Where to find a new one?

[Mike Phillips]

Headlamp Relay - Where to find a new one?

 

Been working on my 1974 Datsun truck, the bright headlights work but the dims don't. The Headlamp Relay is clicking but no power coming out of ail terminals when dim headlights are turned on. (Powering going in and there is power going out for brights so I think the problem is with the relay)

 

Headlight relay is also clicking when the blinkers are actuated?

 

Have the brake lights and tail lights working so I'm closer to driving in the dark.

 

Any resources for ordering a Headlamp Relay? Or how about a generic work-around?

 

I'll add a picture of what mine looks like today...

 

Thanks,

 

Mike

[Drummerboy4as]

Try this out. Add a couple wires, a couple fuses, and a couple relays and you have a much better system

[Mike Phillips]

I'll check out that thread thanks!

 

Here's the pictures anyways since I already took them and uploaded them to may SCG gallery...

 

 

 

 

:)

[DanielC]

You have a 620, this is how a 521 headlight relay works. Once you know how it woeks, you counld use a modern cube "bosch" type relay.

When you turn on the headlights, fused power from the headlight switch goes in to one terminal of the relay. This power is applied to the positive side of the coil inside the relay, and to one of the other three contacts. A second terminal goes to the steering column dimmer switch, a third terminal goes to the low beam headlights, and the fourth terminal goes to the High beam headlights.

My 521 color code at the relay:

Red with yellow stripe, power in

Red with white stripe, High beams

Red with black stripe, low beams

Blue green with white, to dimmer switch. This wire will be a lot thinner than the other three wires.

 

This is how I would wire a Bosch relay to work:

Power in wire, to terminal 30.

Jump from terminal 30 to terminal 85 with short jumper.

Low beam wire, to Terminal 87A.

High beam wire to terminal to 87

Edited November 6, 2008 by DanielC

[Mike Phillips]

You have a 620, this is how a 521 headlight relay works. Once you know how it woeks, you counld use a modern cube "bosch" type relay.

 

Okay, I'll print this out and take it to NAPA and either go with the Bosch or I'll get all the components to rig up the other system.

 

Thanks everyone for your help...

 

Mike

[Pacific coast Datsun]

I see them at the yards all the time. I bought one the other day for $3

[Mike Phillips]

Do you have one you want to sell that you know works?

 

I took mine apart today and found a lever dislodged and out of place so I poked it back were it belongs and lightly crimped the slots that hold it in place and then re-installed it, crossed my fingers and.... nothing...

 

:rolleyes:

[Mike Phillips]

You have a 620, this is how a 521 headlight relay works. Once you know how it woeks, you counld use a modern cube "bosch" type relay.

 

 

Would the Bosch be similar to this one at the local AutoZone?

 

[DanielC]

Yes, that is one example. You can also find them with mounting tabs.

[mklotz70]

I vote for the bosche, unless you have a burning desire to have a stock one. The bosche is rated at 30 amps....I seriously doubt the stock one is.

 

check this for the pin out of the relay...

 

http://www.teamrocs.com/technical/pages/relay_basics.htm

 

My 2 cents on DanielC's setup .....it would work just like a stock relay, but all the power is still coming through the dash and light switch. Add the second relay and wire it up like Beebani's. You'll get brighter lights and you won't melt fuses.

[DanielC]

Good suggestion, Mklotz, but I was thinking on "just get it runnng", then update.

If you understand how the orginal system works, I believe it would be easier to update the system.

The glass round fuses are a weak point in the electrical system, and going to the more modern ATC type fuses would be an improvement. There is also a good chance the connections in the plugs of the wiring harness have gone bad. or have at least degraded a bit.

My opinion, the stock electrical system was not really all that bad, if the loads in the system are kept stock. Like the relay that died, remember everything in these trucks is over 35 years old.

[izzo]

anyone know if its the same for a 1980 720?

[Mike Phillips]

 

This is how I would wire a Bosch relay to work:

 

Power in wire, to terminal 30.

 

Jump from terminal 30 to terminal 85 with short jumper.

 

Low beam wire, to Terminal 87A.

High beam wire to terminal to 87

 

The bold potion above, is this a wire I create with blade type ends and add to the mix?

 

Sorry for not knowing much about wiring... I have the cube relay, it's the universal one NAPA sells and has all the right codes/numbers discussed here and I'm going to go out right now and try to wire it in.

 

Thanks ahead of time...

 

Mike

[Mike Phillips]

 

 

My 521 color code at the relay:

Red with yellow stripe, power in

Red with white stripe, High beams

Red with black stripe, low beams

Blue green with white, to dimmer switch. This wire will be a lot thinner than the other three wires.

 

I have

 

Solid Red - Power

Red with White - Guessing the same as above

Red with Yellow - Dimmer (It's a thinner wire)

Red with Black - Guessing the same as above

 

 

 

This is how I would wire a Bosch relay to work:

Power in wire, to terminal 30. Check

Jump from terminal 30 to terminal 85 with short jumper.

Low beam wire, to Terminal 87A. Check

High beam wire to terminal to 87 Check

 

Not sure where to attach the Red with Yellow stripe wire? (the dimmer switch wire)

 

 

 

 

Thanks ahead of time for your help...

 

:)

[Cuts metal like mad]

You really should take Mklotz's suggestion... what he is refering to is here; http://forum.ratsun.net/showthread.php?t=7081

 

Its simple and MUCH MUCH MUCH better than stock.

[mklotz70]

Since your dimmer switch is providing the ground to turn the relay on....the red/yellow is connected to 86.

 

If you're only hooking up one relay, that should work fine. All of your load is still going through the light sw.....which will probably melt fuses. As long as you're in there....spend the $5 on another relay and you'll never regret it. When I was in sales we used to say....."I only have to appologize once for the price....I have to appologize for the quality everytime you use it" :) Another favorite.....nobody has time/money to do it right the first time, but they always seem to manage to find it when they have to do it the second time!! It's called the "speed of going slow" ....it's faster to go a bit slower and do it right once than to do it quickly twice. :) Anyway....those are my pearls of wisdom :)

[Drummerboy4as]

Since your dimmer switch is providing the ground to turn the relay on....the red/yellow is connected to 86.

 

If you're only hooking up one relay, that should work fine. All of your load is still going through the light sw.....which will probably melt fuses. As long as you're in there....spend the $5 on another relay and you'll never regret it. When I was in sales we used to say....."I only have to appologize once for the price....I have to appologize for the quality everytime you use it" :) Another favorite.....nobody has time/money to do it right the first time, but they always seem to manage to find it when they have to do it the second time!! It's called the "speed of going slow" ....it's faster to go a bit slower and do it right once than to do it quickly twice. :) Anyway....those are my pearls of wisdom :)

 

 

Well said!

Mike Phillips, It's funny, as much time as you've spent trying to figure out which wires go where and where to find the correct relay you could've wired in 2 relays and had a lighting system that is far superior to the joke of a wiring setup that Nissan put in there from the factory :confused::confused::confused:

[Mike Phillips]

You really should take Mklotz's suggestion... what he is referring to is here; http://forum.ratsun.net/showthread.php?t=7081

 

Its simple and MUCH MUCH MUCH better than stock.

 

I will do this but at this time it was just easier to try the cube relay first.

 

Since your dimmer switch is providing the ground to turn the relay on....the red/yellow is connected to 86.

 

Thanks, I'll go outside and hook it up in a few minutes and then install the new flasher and rear light bulbs, (all new bulbs), and then see if the headlamps come on and the blinkers work.

 

If they do, then I can drive it legally. If not, then I'll keep the electrical tester out and keep working on it.

 

Well said!

Mike Phillips, It's funny, as much time as you've spent trying to figure out which wires go where and where to find the correct relay you could've wired in 2 relays and had a lighting system that is far superior to the joke of a wiring setup that Nissan put in there from the factory :confused::confused::confused:

 

I have a real hard time carving out any time to work on a project right now and understand what you're saying.

 

I'm going to wire up the cube relay and try to get everything working, as soon as I get it working then I'll do it right the second time.

 

I actually do try go do things right the first time so this is an exception to the rule...

 

I'm hoping to get everything working, if not then it will be back to trouble shooting and one thing I'm hoping I don't have to do is replace the turn signal/dimmer switch assembly on the steering column. So doing it with the cube relay is my way of doing the easy way (for me), and trouble shoot the system in the process.

 

Now, outside to work on this in the dark...

 

Ugh...

 

:)

[Mike Phillips]

And just to double check for myself and for anyone reading this in the future with the same question...

 

After I hook up the red/yellow wire to 86 nothing will attach to the 85 connection?

 

:blink:

[Mike Phillips]

Hooked everything up, now the dims work on both dim and bright settings but the brights don't work?

 

Also no blinkers after installing the new flasher.

 

Runs good though!

 

:)

[mklotz70]

Since you're hooking up one relay....do it the way you said...jumper 30 and 85.

 

I wasn't trying to be harsh....just a little tongue in cheek :)

 

I've been down that road a thousand times!!! With age comes patience :) Most likely, you'll find that you never get around to the "second time" :)

[Mike Phillips]

Since you're hooking up one relay....do it the way you said...jumper 30 and 85

 

And bare with me, but that means create a small wire with blade plug ends and hook one end to the 85 terminal and graft the other end into the power wire going to the 30 terminal?

 

Thanks for your patience...

 

:)

[mklotz70]

The blinkers and marker lights come off a different terminal on the light sw. The relay you're working with will only affect the hi/lo of the headlights...won't have anything to do with your blinkers or markers.

 

Looking at the '74 620 w/manual wiring diagram.....the red/white powers the high beams on all 4 headlights. The red/black handles the lows(only outer two light up).

Red is the power in. Red/yellow is the dimmer switch(ground signal controlled by the blinker switch).

 

The stock relay had only 4 connections. Your new relay has 5. The stock used the red wire(power in) to supply juice to the headlight bulbs and the relay winding(when the dimmer switch provided a ground). You need to make a jumper from 30(where you connected the red....to 85(the relay winding). Electrically the same, but physically it's external because the relays are different.

[mklotz70]

I haven't been reading your thread too closely....so I'm not sure what's up with the blinkers and the flasher. I'd lay my money on poor connections at the bulbs. You can use the test light to the contact in the socket. Turn your blinker on and probe the contacts with the test light....there may not be enough of a load for them to actually blink, but it should light up.

[BEEBANI]

Mikes, if his new relay has 5 prongs, that just means he has 2 87's. He can leave one empty if necessary. Or, he needs to hook the low beams to one and the high beams to the other. It really is easier to add another relay for the high beams.

 

I can make a diagram for what I did later, if necessary.