1975 Datsun 280Z CA Market Relay Identification And ATC Fusebox Replacement

[HusseinHolland]

The relay diagram is somewhat confusing to deal with as a reference for what's actually there.

Ultimately, the one that is unknown is the 25230-89914 relay

The reality

top: 25230-N3000 - should be Defrost relay

top right:                        - Horn Relay

Left:                                - Interval relay

Bottom front: 25230-89914   ?   Online says interval relay, diagram says AC relay, but mine didn't have factory AC

Bottom right (back): Cat hold relay (not shown)

Top middle (back): 28911-89910  Seat Belt Buzzer?

Interval relay wiring doesn't match the schematic - shows 10 connections

but - only 7 actual

 

Harness side plug: Bl, Gn, Bl-Y

backside, upper 28911 - 89910

harness side socket - Bl-Y, R-Wh, Blk, Blk-Y

 

Edited September 17, 2023 by HusseinHolland

[SteveJ]

1 hour ago, HusseinHolland said:

Interval relay wiring doesn't match the schematic - shows 10 connections

but - only 7 actual

The diagram showing 10 pins used is wrong. I believe I addressed most if not all of this in your thread on the wipers. Note that two of the terminals are repeated, B & E. B = battery & E = earth/ground. You don't need two power or two ground wires.

The 73 wiring diagram shows 9 pins, so I'll use that to explain.

P = Park

M = Motor

3 = High

E = earth/ground

B = Battery

I = Intermittent

W = Washer

2 = High

2 = Low

Notice that the 3 isn't shown on this diagram and is also unused on the 75.

Oops, I made an error. The 75 wiring diagram shows the 7 terminals being used. I think I made the right corrections above. The weather is cooling off soon, so I may be in the garage more in the near future. I can do some testing I've been wanting to do.

Edited September 14, 2023 by SteveJ

[HusseinHolland]

4 minutes ago, SteveJ said:

The diagram showing 10 pins used is wrong. I believe I addressed most if not all of this in your thread on the wipers. Note that two of the terminals are repeated, B & E. B = battery & E = earth/ground. You don't need two power or two ground wires.

\The 73 wiring diagram shows 9 pins, so I'll use that to explain. Notice that the 3 isn't shown on this diagram and is also unused on the 75.

Thank you SteveJ! Any clues on the 25230-89914 relay?

[SteveJ]

1 hour ago, HusseinHolland said:

The relay diagram is somewhat confusing to deal with as a reference for what's actually there.

Ultimately, the one that is unknown is the 25230-89914 relay

The reality

top: 25230-N3000 - should be Defrost relay

top right:                        - Horn Relay

Left:                                - Interval relay

Bottom front: 25230-89914   ?   Online says interval relay, diagram says AC relay, but mine didn't have factory AC

Bottom right (back): Cat hold relay (not shown)

Bottom middle (back): 28911-89910  Seat Belt Buzzer?

So, for the rest of the relay panel, the bottom relay is called the AC relay sometimes and Accessory relay other times. It does provide power to the AC systems when they are present. In the 73, you can trace the wire downstream to the blower motor.

For whatever reason, the horn relay and defogger relay have been swapped on your car. I can't tell you why.

Relay 5 is a little confusing. In the 75 wiring diagram, you can find artifacts of the seat belt interlock relay that was yanked before the car went into production. In the 76 wiring diagram it looks like relay 5 is for the seat belt warning relay. The BY wire is energized only when the car is starting, so I would assume that the is coil wire. (Hint, measure resistance between the BY and B wires on the relay side. The coil will have a resistance reading. It's like measuring resistance between the 85 & 86 pins on a Bosch relay.)

[HusseinHolland]

21 hours ago, SteveJ said:

The diagram showing 10 pins used is wrong. I believe I addressed most if not all of this in your thread on the wipers. Note that two of the terminals are repeated, B & E. B = battery & E = earth/ground. You don't need two power or two ground wires.

Notice that the 3 isn't shown on this diagram and is also unused on the 75.

Oops, I made an error. The 75 wiring diagram shows the 7 terminals being used. I think I made the right corrections above. The weather is cooling off soon, so I may be in the garage more in the near future. I can do some testing I've been wanting to do.

 

I'll continue this in the wiper thread, as it is pertinent to that.

 

21 hours ago, SteveJ said:

So, for the rest of the relay panel, the bottom relay is called the AC relay sometimes and Accessory relay other times. It does provide power to the AC systems when they are present. In the 73, you can trace the wire downstream to the blower motor.

For whatever reason, the horn relay and defogger relay have been swapped on your car. I can't tell you why.

Relay 5 is a little confusing. In the 75 wiring diagram, you can find artifacts of the seat belt interlock relay that was yanked before the car went into production. In the 76 wiring diagram it looks like relay 5 is for the seat belt warning relay. The BY wire is energized only when the car is starting, so I would assume that the is coil wire. (Hint, measure resistance between the BY and B wires on the relay side. The coil will have a resistance reading. It's like measuring resistance between the 85 & 86 pins on a Bosch relay.)

Thanks again - I was assuming the 25230-89914 had to be a more universal relay. Perhaps it's for the blower on mine then.

Relay 5 on mine is the Catalyzer Hold Relay.

 

 

[HusseinHolland]

Cut out the Fusebox today & wired the Hella (MTA) 16 position ATC fuse panel in

Noting the grouped inputs

I batched the fuses following the input groupings above (14 total)

3 Red (1 spare)

2 Black-white

3 Blue-red (1 spare)

4 White-red

3 White -red

1 Black-yellow

No space to batch within the fuse panel, so the splices are outside the box. Small crimp to unify individual wires

Larger crimp to join feed wires

individual circuits added in decending order

separator/ pin retainer  in place 

added spacers to the mount brackets - the door hinge bolt heads are otherwise too close to the wiring passing behind

annoying thing is that only standard cube relays will fit, not the rectangular ones I have for the AC delay & Interval, so those have to go elsewhere. The only one I need to add here  right now is the relay to switch the blower on when the AC is engaged.

Edited September 15, 2023 by HusseinHolland

[HusseinHolland]

Added more stuff, to allow for expansion when I do the V6 conversion.

Ground & power strips. Made a reinforcing plate that bolts using the stock mount points of the relay panel & ign module. Strips are riveted in place 

checking fit

Stripped all the CAT / floor temp circuitry out while I had this apart

added wiring for the seat heaters and WBO2 controller

Have to deal with all the wiring at the console 

 

 

[HusseinHolland]

Worked on the power circuits today

Organizing additional wiring, relay grounds

Wired spare relay sockets with power & ground. Only 2nd from bottom is needed right now (AC-on blower fan override)

Wiring secondary relay panel, additional 6 fuse panel, ground, 30 & 15 rails

15 rail is part of relay panel. Volvo inserted 3 rails in the relay/fuse panels. I kept this one.

making sure that everything can be removed, and has enough cable slack to move out of the way as needed

test fit again, re-wrapped harnesses, place CIS module