DaveP
Active member
For the uninitiated (if you've owned a 1st Gen S-series for any length of time, I don't know how you could NOT know about this), the Mystery Wipe is the act of the wipers taking one swipe, then parking for no reason. Usually associated with use of the turn signals.
I've had a 91 ext cab pick-up for 18 years that I drive for my work. Now has 330K on it. Years ago it began to develop the mystery wipe. Eventually it got SO annoying, that I installed a Typhoon rear wiper switch in the panel to turn OFF the power to the wiper stalk to prevent not-wanted wiper activation. (I even wired the Ty switch to activate the wipers and washers in the "Wash" position on the switch, as that's the most frequent function I use in the DD. It seldom rains in SoCal). With the Ty switch in the center position, the wiper stalk functions normally.
A few days ago, I noticed that the wipers weren't functioning in the Ty switch "normal" position. The stalk controls were dead. Today, I was messing with it, and found that just wiggling the connector between the stalk and IP harness (flat clear and black connector to the left of the column, has a pink "jumper" in it) made the wipers cycle. Odd.
I took the flat terminals on the stalk side out of the clear connector, They were very dark with corrosion. Took a lot to get them shiny again. The female terminals are really difficult to get out. So I just scraped them in place with a little screwdriver, and cleaned it with brake cleaner.
I'll have to drive it a few days to be sure, but I think this was IT. No amount of working the signals made them cycle. Where prior to this, they would cycle within moments, if I didn't cut the power with the Ty switch.
The corrosion changes the resistance in the circuit. Different resistance is what the motor board senses to know what function to perform. I've always wondered what happens for a truck to develop this maladie, and some never develop it at all. (My 93 Blazer never did it once in 285K).
Sorry for the TLDR, but if you did anyway, maybe you learned something. At least it costs nothing, and is worth a try for the Mystery Wipe.
I've had a 91 ext cab pick-up for 18 years that I drive for my work. Now has 330K on it. Years ago it began to develop the mystery wipe. Eventually it got SO annoying, that I installed a Typhoon rear wiper switch in the panel to turn OFF the power to the wiper stalk to prevent not-wanted wiper activation. (I even wired the Ty switch to activate the wipers and washers in the "Wash" position on the switch, as that's the most frequent function I use in the DD. It seldom rains in SoCal). With the Ty switch in the center position, the wiper stalk functions normally.
A few days ago, I noticed that the wipers weren't functioning in the Ty switch "normal" position. The stalk controls were dead. Today, I was messing with it, and found that just wiggling the connector between the stalk and IP harness (flat clear and black connector to the left of the column, has a pink "jumper" in it) made the wipers cycle. Odd.
I took the flat terminals on the stalk side out of the clear connector, They were very dark with corrosion. Took a lot to get them shiny again. The female terminals are really difficult to get out. So I just scraped them in place with a little screwdriver, and cleaned it with brake cleaner.
I'll have to drive it a few days to be sure, but I think this was IT. No amount of working the signals made them cycle. Where prior to this, they would cycle within moments, if I didn't cut the power with the Ty switch.
The corrosion changes the resistance in the circuit. Different resistance is what the motor board senses to know what function to perform. I've always wondered what happens for a truck to develop this maladie, and some never develop it at all. (My 93 Blazer never did it once in 285K).
Sorry for the TLDR, but if you did anyway, maybe you learned something. At least it costs nothing, and is worth a try for the Mystery Wipe.
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