Wiper Pulse Module #14056557

[TommyGuns]

I came across bucket's thread regarding a newer wiper module (https://www.gmsquarebody.com/threads/wiper-pulse-module-15598496.28952/), and I want to share the information I have about the 14056557 module in my '83 Silverado K10.

My module was frequently causing the wipers to sweep once when I turned the ignition to ON. Also, the intermittent wiper delay was almost uncontrollable, with the wipers doing what they want. Since used modules go for hundreds of doll hairs on the electronic bay with no guarantee if they work or not, I researched and repaired the module myself. I created a bunch of extra documentation in the process that should be useful for someone in the future.

Since people find these threads decades later, I posted a copy of the files on the Internet Archive: https://archive.org/details/gm-14056557-schematics

I'll also attach them here for convenience.

 

[TommyGuns]

More attachments..

 

[TommyGuns]

More attachments..

 

[TommyGuns]

Just in case someone finds an error in my wiring schematic, here is the schematic file in KiCAD format.

 

[ali_c20]

That's great information, thanks.

 

[Poodlehead]

In my 77 my wipers would randomly make a pass across the windshield one time. After replacing the controller didn't work, I tracked it down to the 'park contacts' needing to be cleaned. That fixed my random problem...

 

[TommyGuns]

I had this problem with the wiper motor that was in the truck when I bought it, but it wasn't high on my to-do list. The wiper motor then died, tested bad, so I replaced it. The new motor did the same thing.

On my module, I first replaced all the capacitors. This fixed the initial sweep wipe for a bit, but it depended on the temperature. If it was hot out, it was probably going to do the one sweep before I hit ignition.

This second time around, I replaced the IC, which was easy enough. It's still made by plenty of vendors. I went with a Texas Instruments replacement.

The transistor though was a pain. The original transistor's markings didn't come up anywhere. I tried a TIP41CG, then a TIP42CG, before finally figuring out it was a TIP120. Google wisdom suggests replacing a TIP120 with a TIP122 (beefier) or TIP102 (more beefier).

I don't entirely understand the pulse timing circuit, but the diagram is accurate. I carefully traced each connection and identified each component.

 

[TommyGuns]

Take my notes with a grain of salt. Something somewhere is incorrect. The intermittent function of my delay module still doesnt work after the repair.

It didn't help my reproduction wiper control did not work at all, but a used original wiper control I bought tested good and still the intermittent function does not work.

At this point I'm seriously considering buying a working module for way too much money, confirming it works, and at least documenting its internals.

 

[TommyGuns]

Here is a photo and quick video of how to test the wiper delay control for and '83 and older trucks. The resistance tops out around 1 MΩ.

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[TommyGuns]

After further research, what I thought was a transistor is very likely to be a thyristor instead, specifically a type of thyristor called a Silicon Controlled Rectifier (SCR). Basically a diode that can be switched on and off. The original part is positively a Teccor Electronics part. Possibly Part Number S193, which is unfortunately likely to be a custom part specifically for Delco.

I am going to try a Littelfuse S6008LS2TP as a replacement. I have a few on order from Mouser. It should be a more durable part. It has a high voltage tolerance of 600v, a RMS current rating of 8 amps, while also having a gate sensitive enough for the MC14001B to trigger it. The original was probably only rated for 6 amps at 200v, but there's no way to know for sure.

Original Teccor part from my wiper module:

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