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CJG1973

1973 620 Headlight and electrical ...

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Hello all - short term lurker, new member, first post (and all that stuff...)  

I lucked into a 1973 620 (Built 1/73) stashed in a barn for the last 27 years with 47,000 miles.  (and I think those are correct, based on the lack of seat tears and how clean the pedals are).  I've got plenty to do to it, but I'm trying to understand the dimmer switch.  I've searched through multiple posts on the 620s and the overall electrical system.  When I bought the truck, it was missing the dimmer switch and I keep seeing references to an "optical wire" for the  dash lights.  Now, I've got to handle some floorboard issues, plenty of tune up stuff, and cleaning out the fuel system, but I'd like to learn how - and what - the dimmer switch system works, what my options are for dashlights (of any brightness) and what you guys think would be the smartest move as far as making sure my electrical system is worry-free.  

My overall goal for the truck is to make it as reliable as the B210 I had eons ago - and when my son is home on leave from the Corps, he can use it, too.  

Poking around under the dash, I did find what appears to be the "optical wire" broken in multiple places.  I actually haven't even put a battery in this one yet, but I'd like to begin to get a plan together.  Selfishly, I don't want to burn this one up.  90% of the harness looks good.  

Oh, and is there a cheat-sheet in the forums for wiring diagrams and/or a list of where all the grounds for this truck are located?  I know how bad resistance from bad grounds can be for reliability.

 

Thanks everyone...

Chris

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Damn.  You are kinda close to me.

 

 

Quite a few pics on this site got murdered by photobucket so its kinda hard to search them out.  I am kinda shocked not one stopped in with a wiring diagram to share.

 

 

As I understand, the dimmer switch in any of these rigs is a joke.  It switches them from dim as shit to might as well not be on.  I think an led swap for your dash lights is in order to get any ability to read them easily at night.  I had to on my 521.

 

You might get some more responses if this thread was to get moved to the 620 section as well.

 

Im kinda buzzed.  Hope this makes sense. 

 

 

edit: think I might still have the dimmer switch to the 75 620 I parted out, I will look.

 

Edited by bilzbobaggins
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620 wiring diagrams can be found here

 

https://www.nicoclub.com/archives/datsun-pickup-wiring-diagrams-for-320-520-521-620-720.html

 

The dimmer switch as mentioned doesn't really do anything... and with an led upgrade you could burn it out... so probably best to replace it with something newer if you do that 

 

The optical wire just provides lighting to the knob itself. It feeds back to a cylinder with a bulb

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Early use a rheostat, a variable resistance (gets warm/hot)somewhat like a radio knob. Later ones use a solid state transistorized adjustment. LEDs  aren't really dimable but in either case LEDS draw less power for same brightness so aren't going to harm anything.

 

Q8w5qp9.jpg

 

Si5RaQY.jpg

 

I think the new ones waste less power and will interchange with the old.

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Are you Talking 720, 710, 510, & 310?  I think the 210s used this style dash light dimmer.  Are the aftermarket switches the solid state transistorized ones?

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The one in the picture is Nissan. Not sure when they changed one of my 710s had the rheostat (with a large coil that gets warm) the other was solid state so mid '70s???

 

They look somewhat like this with a heat shield around them.

NOS-OEM-Datsun-Nissan-Dash-Light-Dimmer-

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