fan switch is shorting number 8 fuse when turned on ..help needed.

[bimoverde]

ignition on..(engine not started)
air fan cursor moved to the right the outside air fan works well..moved back to the left. fan stops.
when i turn ACfan switch on fuse number 8 shorts.
disconnected compressor wire. AC fan switch still shorts when turned on.
Tested fuse poles,.. when ac fan switch is of ..upper pole juice..lower pole neither hot neither ground
when ac fan switch on bottom pole ground itself causing the short.. so the grounding is between the lower pole and (not sure where).. Could not find a wiring diagram for the ac in my work shop book..
Is the switch bad? Relay issue?
any help appreciated...

 

[HB Chris]

The coupe has a fan changeover relay above the fuse block which disables heater fan when selecting A/C fan. In 74 this was eliminated and the A/C fan switch gained a fourth wire to do the same job. What year is your coupe? It helps to have it in your signature.

I had a short in the wire to the dryer at the radiator wall, caused the same symptoms. A/C wiring is in the Blue Books but not on the diagram, it’s been posted here a few times.

 

[sfdon]

This one ?

 

[bimoverde]

Hi My car is a 1973. I do have the bleu working shop manuals. I had the wiring diagram enlarged, but i do not see anything about the ac wiring? ami looking in the wrong part of the work shop manual?
Thanks for taking the time chris.. this is my first e9 and i have to learn a lot about the car.. I had a blinker problem until i identified that it was caused by the warning button(not the blinker relay).. much to learn about the electrical on this car.,
fuse 8 shows rear left window on the fuse box sticker(but when fuse is blown..rear window still works?/)
i suppose i should check this relay above the fuse box(replacing it is probably what i should do if they are available)..any other suggestions?

 

[sfdon]

Or this?

 

[sfdon]

Or?

 

[bimoverde]

ok
i will check the car out tomorrow..but from the look of it the first diagram looks more the part.. I am up in benicia ..thanks SF Don

 

[HB Chris]

I would look for a ground between the switch and the engine bay. If you remove the passenger side console you can access the switch and check for a ground leaving the switch.

 

[Ohmess]

That first diagram Don posted is from my car; I had some trouble with corrosion in the flying fuse socket (number 7 in the diagram) that was giving me some grief.

Another thing to look at is the wiring where the wires actually run to the fan near the right side headlights. My grommet was gone, and the wires were rubbing on the sheet metal as a result of this. I caught this before it caused a grounding problem, but while you are looking at this circuit, make sure this grommet is intact.

 

[HB Chris]

That first diagram Don posted is from my car; I had some trouble with corrosion in the flying fuse socket (number 7 in the diagram) that was giving me some grief.

Another thing to look at is the wiring where the wires actually run to the fan near the right side headlights. My grommet was gone, and the wires were rubbing on the sheet metal as a result of this. I caught this before it caused a grounding problem, but while you are looking at this circuit, make sure this grommet is intact.

That was my problem too, wires near the radiator panel.