89 SHO wiper troubles

Forgive me...i have looked and had some help SHOROD but still have so headaches. To recap.....wiper sometimes turns on by itself, it will stop when you turn the switch on, but then it dont park. Sometimes the wipers barely move....the wiper transmission doesnt want to rotate. Thanks to shorod, i cleaned the contacts in the multifuction switch but to no avail. I replaced the transmission, and now the switch....again nothing gained. Any ideas? I dont believe the wiper motor is bad as it is working. What else can it be? Thanks in advance.

I don't have the wiring diagram for the 1989, but am using a 1992 diagram for reference and hoping they are similar (although the body style of the SHO changed in 1992).

At least for the 1992 model, the park and run functions are performed by the wiper motor assembly. For the interval wipers there is an "interval governor" box separate from the wiper motor. The troubleshooting guide indicates if the interval wipers work with the switch in the off position, the possible causes are an open condition in the wiper switch (in the wiper motor assembly) or an open condition in the Orange wire.

Possible causes for wipers that won't park are listed as an open condition in the wiper switch or no voltage to the wiper motor.

The common "cause" for both conditions is the wiper switch in the wiper motor assembly.

-Rod

Ive replaced the motor and multiswitch with Nos motorcraft parts and when off....wiper cycles, goes to park and cycles again. It continues until i turn the switch on, then wiper stops where it at. Any clue? Thanks.

Does the new multi-switch include the turn signal/wiper stalk?

-Rod

yes it does.

I think I'm out of ideas on this one. Sorry.

-Rod