76 eldorado wiper motor

[76 cadillac bob]

I had an old posting regarding wipers. My third motor (under warranty) then I replaced the wiper switch with a brand new one,   and still no action but pushed the washer button and heard it clicking. Then after driving for about 15 minutes, the wipers work as if nothing is wrong. Once the wipers work they work perfectly, all speeds, delay and wash pulse, etc. Could this be some sort of relay that is not working correctly, if so where is it located on this car to replace unless someone has a better idea. Thanks.

[TJ Hopland]

New production switch?  Or new old stock?

How about the motors?   Are they rebuilt?  New?  From regular parts source or a Cadillac specialist?   And you are replacing the whole works every time including the pump and module that are sort of built onto the gearbox cover above the motor?  All from the same source so they could all have been on the shelf from 20 years or assembled by the same inept worker? 

I don't have a 76 diagram but typical GM in that era didn't have a relay.   Power is always supplied to the motor when the key is on as well as to the switch.   The direct to the motor power was used for the parking circuit so the wipers could park after you turned the switch off.   It was also used for the wash function assuming this was a model that didn't mechanically force the switch to on if you pressed wash with the switch off.   The parking, wash, and delay were all a combination of mechanical and electronics contained in what I believe they call the pump assembly that bolts onto the motor assembly. 

[76 cadillac bob]

Brand new switch not rebuilt, came in box from original stock. Both motor and washer as a unit have been replaced twice( whole works) I am going out today will see if it works and when....Not that it rains that much here in San Diego, but I like things working correctly. If it stops working I may try my hand at replacing the motor/washer unit myself. It could be the supplier of the units my mechanic is using that is the issue that is a good point.
CB

[TJ Hopland]

I just ask about the supplier because I have been through that several times getting 'old' parts from the same vendor.   Slow moving stuff from regular suppliers often sits on the shelf a long time perhaps in less than ideal ambient conditions.    They keep the fast moving Mustang parts in the new climate controlled warehouse and the 40 year old Cadillac parts in the old building with the leaky roof.   

[7gen]

I've had very good luck with http://www.usapartssupply.com/cadillac.php and http://www.rockauto.com/en/catalog/cadillac,1976,eldorado,8.2l+500cid+v8,1409385,wiper+&+washer,windshield+washer+pump,8840