Heater blower wiring

[johnymd]

I had a similar problem when I tried to get the 280z blower motor to work and ended up using the sub loom that linked the fan switch to the motor and resistor pack. I then just supplied 12v to the motor and that was it. For the 240z I'm currently rewiring, I don't have a loom I can check or use. I just have the motor/resistor pack and the switch. The 3 speed switch has 6 wires and the motor/resistor pack has 4. How are these interconnected in a standard 240z? All the diagrams are next to useless and don't even show the resistor pack.

Any help would be much appreciated.

 

[Paul_S]

I might be able to help you out here. I took mine out of the car today so I've taken these pics.

Back of blower switch:

Blower switch and plug:

Closeup of plug:

This goes to a short middle loom:

Here's a closeup of one end:

Here's the plug on the blower:

The black and red wire are for the fan. Here's the inside showing the coil:

I hope that helps. Let me know if you need more.

 

[jonbills]

The 260z FSM has a good diagram, but it's shows the switch plug also having 4 wires.
The switch plug has a power in and not surprisingly 3 'hot' outputs which go to no, one or two resistors in the resitor pack before the fan unit.
What do you have of this? just the resistor unit and the switch unit ? or is it all different?

 

[jonbills]

Posted at the same time as Paul.

 

[johnymd]

Great reply's.

I have the 6 wire switch as in Paul's picture and the same connector at the fan. All with the same colours as in Paul's picture. I have no other wiring so I will need to recreate the sub loom. So I need to know how the sub loom connects the 6 wire switch plug and the 4 wire motor plug. Do I just connect red to red, yellow to yellow, white to white and green to green then 12v supply on the blue wire and earth to the black wire?

 

[johnymd]

I know the blue is usually the supply cable and the motor is permanently live. The switch connects the resistor pack wires to earth to make the circuits.

 

[johnymd]

I think I get it now. The switch just switches in the resistors to earth. It has a live but that's just a passthrough live from the blue wire to the red that goes straight to the motor positive. The black goes to the switch as an earth for the green, white and yellow wire the switch down to it. Does that make sense?

 

[johnymd]

From Jon's diagram:
The white wire from the dash goes straight to the motor positive.
The black wire goes to the switch then through a combination of the 3 wires to the resistor pack then to the negative of the motor. Depending on the switch position the motor negative will have a different resistance in circuit which will drop the voltage at the motor.

Thanks guys you've both been a great help.

 

[jonbills]

If the motors got a permanent +ve feed, I'd agree with the switch just switching to earth through the 3 resistor levels.
It looks like in Pauls pic that green/yellow/black/white match the 4 wires on the 260z switch, so sounds reasonable that blue and red are doing something else

 

[johnymd]

Built a sub loom this afternoon and wired it as in my post and it all worked perfect. After testing the switch I find it has 2 separate sections. One switch the live supply straight to the motor (blue wire into switch and red out) and the other section switches in the resistors to the black earth wire.

 

[jonbills]

Built a sub loom this afternoon and wired it as in my post and it all worked perfect. After testing the switch I find it has 2 separate sections. One switch the live supply straight to the motor (blue wire into switch and red out) and the other section switches in the resistors to the black earth wire.

Pics?

 

[johnymd]

Here’s the sub loom I made. I tried to use similar colours to factory. Basically the 2 six pin plugs link the switch and blower plug and the 2 pin connector is for power and earth.

 

[Rob Gaskin]

I think I get it now. The switch just switches in the resistors to earth. It has a live but that's just a passthrough live from the blue wire to the red that goes straight to the motor positive. The black goes to the switch as an earth for the green, white and yellow wire the switch down to it. Does that make sense?

John, my fan motor is fed from the blower fuse (air con 20A) through a blue wire to a red wire direct to the motor. The red is spliced and feeds back to the switch. This is not needed but was perhaps an air-con feed? Just mentioning for future reference. My car is a converted US car but unsure what loom is uses.