Wipers not turning off as demanded? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**hatzie** · 10-19-2018, 05:06 PM

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.

10-19-2018, 05:06 PM	#4
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 5,050	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. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful. Last edited by hatzie; 10-19-2018 at 05:11 PM.



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