'83 300CD Where is the intermittent relay located *under the dash?* or where?

When wipers are set to"I", there is a barely discernable delay of WW's. Duration has been getting less & less over last 2 years.

Also, anyone know the p/n of this thing? I've got a box full of elec items/switches/relays & might have what I need, somewhere, , , ,

-corne-

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