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1971 Mark III Windshield Washer Issues & Update

Bill,

My 71 Mark III hydraulic wipers seem to work fine, but the washers do not. I cannot hear the washer pump engage at all. I suspect that at least one problem is with the switch. Other than an occasional and barely discernible "click", it hardly moves when I push the knob to activate the washers. If the switch should move farther when pressed, I would like to dissemble it to attempt a repair. The shop manual only instructs one to "remove the knobs". I assume it refers to the primary control knob and the inner knob/bezel against the lens, but it does not explain how to remove them. I've identified a slot at the base of the primary knob, but cannot see any set screw to release the knob. I've attached a picture so that you can see the resting position of the switch.

Do you have any experience that may point me in the direction of a likely problem?

Can you advise me how to remove the knobs to get into the switch?

Finally, can you tell me if these cars had an intermittent option, or just very slow and speed up as the knob is rotated clockwise? If I need to find a replacement switch, do I need to make sure I match the wiper system in my particular Mark III? I sense about eight detents when I rotate the switch clockwise.

Bradley

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Hi Bradley -

Since removing the wiper switch is not a real easy task, why not first test for power at the washer pump when the washer switch is activated . That way you will know if the pump or the switch is faulty. The hydraulic wipers are variable speed design.

Bill

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Bill,

Thank you. I confirmed that no power was making it to the pump, but found the pump to be operational when I bypassed the switch. I was able to figure out how to remove the switch from the housing and found that the piston mechanism that closes the pump switch contacts was pretty gummed up, and therefore wouldn't move when pushed. I loosened it up with solvent and flushed as much of the gunk out as possible. It doesn't move a freely as I'd like, but it does work.

Bradley

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Bradley,

Good work, persistence paid off. The more that you operate that switch now the better it should work. You were probably the first person to operate it in decades.

Bill