What is this?

[codfish]

Truck is registered as an 84, but the cab MAY be a different year. This is under the dash , just under steering column. Never traced the wires, in the midst of reforming my seat.

Thanks
Codfish

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[Snoots]

That is the Delay Module for Pulse Wipers.

 

[scrap--metal]

If that module is still good, and your delay wipers work properly, it's a valuable little part. I don't think they're reproduced and they seem to fail after years of use.

For example, that module is dead in both of my squares.

 

[PrairieDrifter]

If that module is still good, and your delay wipers work properly, it's a valuable little part. I don't think they're reproduced and they seem to fail after years of use.

For example, that module is dead in both of my squares.

They're reproduced.

 

[Cyrillious]

Wiper delay module. Wiper switch connects directly to it.

Would be nice to know what diodes or capacitors fail to possibly fix it.

 

[Scott91370]

They're reproduced.

Yes and are not cheap. I htink when i was looking like $90

 

[codfish]

Thanks guys

I guess mine does work. Now.

Just found a broken wire on the firewall that’s part of that system and fixed it.

Intermittent wipers are working again!!

Thanks again

 

[PrairieDrifter]

Yes and are not cheap. I htink when i was looking like $90

Yep, I believe that's about what I paid a few years ago.

 

[scrap--metal]

Yes and are not cheap. I htink when i was looking like $90

Thanks for letting me know that they are reproduced. For that price, I'll continue to live without delay wipers. Someday...

 

[SquareRoot]

I bought an AC DELCO from RockAuto. It was like $70-80. The "Delay" function works awesome! In fact, the non-returnable POS didn't work out of the box. Still waiting for the delay to end and hope it starts working. At $90, I'm not taking another chance.

 

[Snoots]

Thanks guys

I guess mine does work. Now.

Just found a broken wire on the firewall that’s part of that system and fixed it.

Intermittent wipers are working again!!

Thanks again

Just an FYI, if you have some heat sink paste lying around, take your module apart and replace the grease on the FET. Just like your ignition module. Most modules fail because the grease has dried out and the FET dies because of overheating.

 

[gofast321]

These are getting more difficult to find and the ones that are available are getting more and more expensive. I have repaired a few and 90% of the time the issue seems to be bad capacitors. The caps go bad as they age. Here is a schematic from thread https://www.gmsquarebody.com/threads/wiper-pulse-module-15598496.28952/ that I have used multiple times to repair these.

I bought this capacitor set from Amazon for $11 and it has all the caps you need to repair dozens of these pulse modules. https://www.amazon.com/gp/product/B07M914GKR/

And to Snoots point... definitely clean off the old heat paste and apply new paste.

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[scrap--metal]

Wow! Thanks for posting that schematic @gofast321. That mysterious box doesn't seem so mysterious anymore.

This seems like a fun winter project.

 

[Scott91370]

Yesterday was the first time the truck was driven in the rain and I found out my intermittant wipers do not work. Guess it's time to try this rebuild.

 

[SquareRoot]

These are getting more difficult to find and the ones that are available are getting more and more expensive. I have repaired a few and 90% of the time the issue seems to be bad capacitors. The caps go bad as they age. Here is a schematic from thread https://www.gmsquarebody.com/threads/wiper-pulse-module-15598496.28952/ that I have used multiple times to repair these.

I bought this capacitor set from Amazon for $11 and it has all the caps you need to repair dozens of these pulse modules. https://www.amazon.com/gp/product/B07M914GKR/

And to Snoots point... definitely clean off the old heat paste and apply new paste.

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This is your first post and you drop a bombshell packet of useful information like this AND you include pics? IMPRESSIVE! Welcome to the club!