electrical and ignition '73 wiper speed switch bad?

[Posaune]

Trying to chase a bad parking/wiper keeps running issue. At first I though eh this'll is just the motor parking mechanism.  Nope.  I think I've ruled that out.  I'm competing with a few things simultaneously - PO rewiring (bypassing the relay with a switch on the kick panel), potentially bad relay and potentially bad switch.  I've removed the janky PO switch, restored the black wire to the "F" terminal on the relay.  Wipers run regardless of stalk switch.  However, if, with the relay box open, I lift the contact on the relay, the wiper motor parks as it should.  That's what leads me to believe it's not the motor.  I also have a spare motor.  Acts the same.

 

First I think the relay could be bad, or the stalk switch is sending power to the relay constantly.  However I also checked the speed switch and it doesnt seem to work as I would expect.

 

This car has the 6 pin relay and 2 position speed switch (slow and less slow).  

 

Switch has three terminals - 53, 53a and 53b.  My interpretation of the wiring diagram is that with the switch IN there should be continuity between 53 (input black/red wire) and 53b (or i could be wrong and it's 53e).  However, there's no continuity between 53 and either other terminal.  However, there is continuity between 53e and 53b.  With the switch OUT there's continuity between 53 and 53e.  This seems correct per the diagram.  That said, when the wipers are running, the switch does affect speed.  

 

Has anyone ever opened the speed switch without destroying it?  Any tips there?

 

Should the "F" terminal only have power when the stalk switch is clicked?

 

Next step is to also check wiring at the stalk, the stalk switch and the relay.

 

Edited September 24, 2016 by Posaune

[Posaune]

Ok switch is def bad.  Works in high speed position but no circuit in low speed.

 

Found somehting interesting messing with this today.  The brown/red wire is hot when the motor is NOT in parked position and no voltage when parked.  I think this  is a signal fed back into the relay to tell it to turn the motor off.  In all the searching and reading I've done there is no mention of this.  

 

I now think I have a bad relay but also was able to use a standard E30 black SPDT relay to at least get the wipers to turn on and off with the stalk switch (which is also good).  The washer pupm also works like this.  HOwever the parking doesnt work.  I did get it to sorta work by connecting the brown/red AND the black (combining 31b and F of the original relay) to the 30 terminal which would keep current flowing when the stalk swithc is on OR the motor is not parked.  HOwever this is not safe long term.

Edited September 24, 2016 by Posaune

[Mike Self]

If you've determined that the stalk switch is bad, drop me an IM--I did a column on troubleshooting and repairing the wiper switch portion of the 72/73 turn signal/wiper switch stalk.  

 

mike