Brights always on

[SteezySkreez]

So guys im new to this datsun gang. Ive had mine since christmas. It is a 76 620. There is a few issues but i will just start with the fact that my headlights always have the brights on. So to fix this so far i have just unplugged the brights. Any ideas where to check? Anything helps!!

 

[GRpufnstuf]

Not trying to be a smart-ass..

 

Do you know where the switch is? I met a guy who couldn't switch his because the steering column housing was in the way. I demonstrated on mine and he figured out he had to modify the repair he had made to the housing.

[SteezySkreez]

yes, i do know where the switch is. It doesnt matter if it is forward or back. The brights remain on always. 

[wayno]

Bad relay?

[datzenmike]

Unplug the turn signal switch at the column. It has six wires to it. This will disconnect the hi low switch from the relay and it should return to low beams.

 

If it does, the switch is stuck. If it doesn't, then the relay may be.

[DanielC]

I do not know for sure about a 620, but on a 521 the headlight relay has four wires on it.  Red with yellow, Red with white, Red with black, and a light green with white.  The three red with whatever wire are the actual headlight power wires, and are thick.  The light green wire is thinner.

 

Power goes to the relay on the red with yellow wire.

high beams are the red with white wire.

Low beams are the red with black wire.

The light green with white wire grounds the relay coil at the dimmer switch on the turn signal.

 

Unplugging the light green with white wire at the relay should make the relay switch to low beams. 

 

If somebody else with a 620 can confirm these wire colors, that would be nice.  And if I am wrong, I can edit this post to the correct colors.

[datzenmike]

 

 

OK, on the steering down near your knees by the dash there will be a several small wire harnesses one connecting the ignition switch another connecting the turn signal switch and one for the 4 way emergency flasher switch.... to the dash harness.
 
Find the 6 pin plug and unplug it. It will have
 
Green/Yellow ..............Red/Yellow
Light Green/Black...... Green/Black
Light Green/Black...... Green/Black
 
Wires going into it.
 
When unplugged, if the high beams go out, the the problem is in the dimmer switch in the column.
 
If the high beams stay on, then the headlight relay is stuck on

[SteezySkreez]

Okay so i unplugged them and nothing has happened. Where do i find the headlight relay?

[datzenmike]

I sent you a p/m. Turns out your '78 is the first year the 620 did NOT have a headlight relay. The dimmer switch sends either high or low beams to the lamps. I checked my '78 FSM and this is the way they are. If you unplugged the turn signal/dimmer switch they should all go out as there is no power supplied to them.

[BenJammin]

Your location lists 'Wilsonville'... not sure if that's in California or not, but if it is your brights are always on because that is just the way people in California roll !  At least here in SoCal.

 

It was always taught to me to lower your lights when approaching another vehicle, whether from the front or rear, but I'm amazed since moving here how many people who not only won't dim their lights when coming head-on, but ride my ass with their brights on too <grrrrr>.... happens ALL the time, even at dusk and dawn when you barely need lights on anyway.

 

Sorry, I know this is an OT rant and doesn't help your problem whatsoever, but at least if you are in Cali, you probably fit right in with the brights on all the time :)

 

But one constructive note (and a big wag), some PO may have changed hacked the harness, either near the switch or by the lights themselves to make the brights and lows be on at the same time, no matter what (the reasons would be the bright position of the switch went bad at some point ?) so just make sure everything looks stock at both ends.

[datzenmike]

So guys im new to this datsun gang. Ive had mine since christmas. It is a 76 620. There is a few issues but i will just start with the fact that my headlights always have the brights on. So to fix this so far i have just unplugged the brights. Any ideas where to check? Anything helps!!

.

 

Reading back I have to assume that this truck has never worked properly. If you unplugged the turn signal/dimmer switch and the lights stayed on then a previous owner has messed with the wiring to the headlights. This is a problem with people who take short cuts or don't know what they are doing, or usually, both.

[BenJammin]

 

.

 

Reading back I have to assume that this truck has never worked properly. If you unplugged the turn signal/dimmer switch and the lights stayed on then a previous owner has messed with the wiring to the headlights. This is a problem with people who take short cuts or don't know what they are doing, or usually, both.

 

Yep my truck harness was hacked all to hell !   Some po had used those vampire clamp things to route around multiple issues.  Don't even get me started on what they did to get around a bad turn signal switch.... oh my my  :crying: