Expert: Vern Bullock - 11/28/2009

Question
QUESTION: 1983 Silver Spur w/ 64K: The windshield wipers will NOT turn off when swithced to the off position. I have changed all the under hood relays. When I bought the car (at 63 K), the three windshield wiper relays were pulled out - put them back in (with all new Bosch 12V 30Amp relays) and the wipers still stay on when switched to OFF.  I heard that this is a common problem with 80's Rolls.  What should I do to resolve this? - don

ANSWER: Hi Don:
If the wipers won't turn off, it is most likely the knob that is broken.
Pull the knob off and check it. The wiper post under the knob is a 1/2 round post and
the knob has a metal 1/2 slot to match the post. If the knob slot is not
fitting firm, it is not turning the post when you operate the knob. It could be stuck
in the ON position. The best way to check this is to remove the knob and use a pair of
pliers to check the post for proper operation.

---------- FOLLOW-UP ----------

QUESTION: Hi Vern:

This 'knob' that you are referring to:  is this the chrome wiper switch   on the dashboard? The knob turns left and right andhas 4 position: left is "Intermitent", straight up is "OFF", and right is "slow"/ "fast").

Under the hood I watched the connecting rod (attached to the motor at one end and the wipers at the other.  When the OFF position is selected, I hear the relays click and the connecting rod reverses directions, but keeps running.  In the three other modes, (intermitent, slow, fast), the connector rod rotates clockwise, but in the OFF position, it reverts to counter-clockwise and keeps running unless the relys or fuse is pulled.  
Please clarify the 'knob' issue.  Thanks  much!

Don

Answer
Yes. The chrome wiper switch is the one I was referring too. If it is working fine, then
the problem could be a bad relay or motor. I have seem after-market relays that are defective
as well. Also the motor could be wired wrong, but first make sure your switch are working correctly.