wiring noob question

[Eagle_Adam]

im not a pro but id like to think i can hold my own when it comes to datsuns, however wiring is the only thing im not good at. I have a 74 620 that i just got a stock tach for. I pulled the gauge cluster surround to install the tach and was expecting to see a loose connector hanging back there to plug the tach into. My first question is do automatic 620 even come with a "plug n play" option so to say for a tach or am I SOL?

[Skib]

when I put mine in the plug for it was there, it was just taped back to the harness from the factory

(since it wasnt a factory tach truck) it took me a little bit to find it.

[Eagle_Adam]

Hmmm, the search continues. Thnx Skib

[datzenmike]

... I pulled the gauge cluster surround to install the tach and was expecting to see a loose connector hanging back there to plug the tach into. My first question is do automatic 620 even come with a "plug n play" option so to say for a tach or am I SOL?

 

Sorry, missed this. The clock option was on all 620s but the tach only started in '76. There were also two types of tach I believe.

 

 

(far right)

 

The top one plugs in with separate wires the bottom right has a plug which is definitely how the 620s are wired. The top one may be from the 1200 and are pretty much interchangeable, the difference being the clear plastic bezel on the 620 is cone shaped, while the 1200 is flat. Both appear to be an inductive type, in that the wire marked 4 and 5 simply loops through that tab and are not electrically connected to it. One end goes to the neg side of the coil and the other?? I don't know but not to ground or the coil won't work. Maybe to a resistor to ground?

[Eagle_Adam]

looks like i have the latter of the 2, here's mine guys:

 

 

 

i was frustrated when i first posted this so i moved onto the POR 15 process on the floorpans. Im still going to take a look when im done but are you saying i wont have the plug in a 74 620 wiring harness mike?

[datzenmike]

Yes, That is the other style, found mine just half an hour ago looking for my antifreeze tester. Single Black/green stripe wire going in.

[Eagle_Adam]

anybody have any suggestions on wiring it in?

[datzenmike]

 

On the right side connector:

 

(close side)

Blue/white stripe goes to a constant +12 (probably for the clock option and not needed on a tach)

 

Black to ground

 

Black/Green* stripe to W terminal on fuse box (15 amp) or any +12 volt switched on by ignition.

 

(far side)

Blue goes to the negative side of the coil. (points or EI dizzy doesn't matter)

 

Red/Black stripe and Red/Blue stripe is for the illumination lights. I couldn't figure out how to wire into the dash lights/dimmer so just wired them to come on with the key. Ground one +12 the other from a keyed source... could also use the Black/Green* wire (above)source

 

 

 

.

[Eagle_Adam]

Mike you are like a freekn datsun superhero man! Ill give it a shot after work tomorrow!!!!

[Eagle_Adam]

Thanx again to Mike for awesome instructions and thanx to nismo Dr for helping!!!!

[crackerjack69]

I'm gonna wire my tach in someday. I have the newer harness in a box somewhere, the one w/ the tach connector on it. Thought about putting the whole harness on my 72, but I want to keep my blinker switch cuz I don't use a clamshell and the new style blinker switch is ugly. Guess I gotta get the motor running bfore I need a tach :D