74 SSS cluster into 76 710

[Kathos]

Hey Everyone. I recently scored an SSS cluster (with harness) from a 74 SSS model from New Zealand. The dream would be to get the cluster working correctly with all my instruments but I am noticing quite a few differences in the wiring between the two harnesses. Does anyone have a wiring diagram for a 74sss or a 76sss? Has anyone documented this before?

I'm trying to decide which harness I should modify and which I should leave alone. Pictures attached in drive.

https://drive.google.com/drive/folders/10uUALTKOod60Tj9t2huQuI4AZyZ9ePd2?usp=sharing

[datzenmike]

So cool. I have the tach option in my '76 and it plugged right into the right side pod. Combines brake/oil/charge.

 

 

 

 

 

 

 

[Kathos]

Hey Mike. Ive seen those before. That is a really cool and simple option. Can you tell me, is your tac a 3 wire or a 4 wire? Does the fat BG wire with the male spade plug into it?

[datzenmike]

 

Found the picture I was looking for.

 

Black/Green is the signal from the coil negative. I think it was there on the gauge cluster and just needed plugging into the tach. I have the '76 FSM and it shows a tach option.

[Kathos]

The 74sss tach has 4 wires coming from it (Y, B, BW,BW) . The two BW wires connect to BW , BG. I believe that this tach needs to be connected in series like the 510 4 wire tachs. Does that sound right?w

Also, do you have access to a wiring diagram in color?

[datzenmike]

It does sound right. That would be an inductive tach. Has to be inline with the points.

 

No the FSM one is a fold out 3 page B&W

[Kathos]

I have a few questions.

1) The blue wire that goes to the speedo. "Odometer switch" <- whats it do? (Drive counter Detector?)

2) The other BG wire behind the cluster that doesnt go to the tach. "AMP" <- whats it do?

 

See attached Wiring Diagram for 76 710 cluster

https://drive.google.com/file/d/1V_cQV-nfT1FppC9fleIEIB3mB7-TL-Xp/view?usp=sharing

[datzenmike]

 Blue wire to detector. This is to set off an EGR light on the dash? at 30K intervals to alert drivers to clean the EGR valve of deposits. Not used on California and Canada in '76.Once activated the counter has to be manually set back to zero... this will turn the EGR warning lamp off.

 

Black/Green eventually finds it's way to the coil negative terminal. This is the signal for the tach and is unplugged if no tach.

[Kathos]

Interesting! Probably why the previous owner took the EGR bulb out when I bought my car at 33000 miles.

 

I think I have a game plan for wiring the SSS cluster. I cant for the life of my find the in-line resistor on the BG cable. My BG cable starts at the distributor then it Y's off, 1 leg to the neg coil, the other through the fender panel into the firewall and I am assuming into the tach. Were is this resistor?

[datzenmike]

I don't think there is one. It's not in my wiring diagram. My 620 had a similar set up and no resistor. However the '80 S110 200sx and the 720s did, I've seen them but the 300zx, Stanza, Sentra, Pulsar, Maxima, S12 (all '80s vehicles) did too..

[Kathos]

I dont know how you remember as much as you do but I am thoroughly impressed! Ill keep you updated

[datzenmike]

 

I think every '80s car had the 2.2K resistor in line between coil and the tach if they had that option.  The resistor looks like a small lump on the engine room harness wrapped in electrical tape.

[Kathos]

Hey Mike, Look what i found. https://drive.google.com/file/d/1fGRgTpQzG420STqs5HerD3WgRPnt78v7/view?usp=sharing

It is right by the firewall seal above the left side of the clutch pedal.

Interestingly enough, the car wouldn't start with the tach in series unless I bypassed the resistor