Wipers not turning off as demanded?
 

Has anyone ever seen a cause that would prevent the windshield wipers from not stopping running after the stalk is turned to the off position. The only thing that stops them is turning the truck completely off. This is happening on a 1989 Suburban, but my last squarebody did the same thing, it was an 85.

Re: Wipers not turning off as demanded?
 

Never found the cause but I had a 79 Camaro that would do this on occasion. I think it was something sticking shut in the wiper motor assembly as I replaced the wiper switch in the dash and it kept doing it. IIRC, yanking the wire plug out of the washer assembly made it quit but then no wipers.

Re: Wipers not turning off as demanded?
 

I am not sure about your vehicle, but my 83 C20 has an intermittent wiper module that does not work. This causes the wipers to not shut off. I have to move the dash mounted switch all the way to the right, then quickly move it all the way to the left, then let go of the switch. I think you have a stalk mounted wiper control, so this may not be your issue. My 83 module is no longer available, so I just deal with it. I got a NOS wiper module but it was also defective. I think your stalk mounted wiper control is still available.

Re: Wipers not turning off as demanded?
 

A malfunctioning parking cam inside the wiper motor transmission can cause this.
A failed delay module can do it as well.

You can rule out the delay module with a simple bypass test. Remove the plugs on both ends of the delay module and plug them together.
You'll have three terminals from the delay portion of the switch that hang off to one side...
However... the wiper motor will receive grounds from the switch on HI, LO, & OFF just as if it didn't have the CD4 delay wiper option.

If it continues to malfunction then it's the motor. Otherwise it's likely the delay module.

I'm looking for a dead 85-91 delay module to tear down and see if it can be resurrected with some discrete electronic component replacements... My only example works fine so I don't want to just rip it open.