1982 Whiper Delay Module

[36chevy]

Seems like nobody sells this part. Does anybody repair these for our trucks? I dont know anyone who has one that actually works...

[GOPAPA]

Long shot here ,, but if the plastic box will come apart then this might be worth tryin

I had a relay switch on my 72 Toyota truck stop working and I took it to a radio shop and the guy unsoldered a resister and replaced it and that $ 2 dollar fix was way cheaper than if I remember $40 for a new one..

[36chevy]

That would be the last resort. Someone did tell me all resistors go bad over time. Does anyone know of one that's still working?

[hatzie]

Those 14056557 modules have several electrolytic capacitors inside. I doubt GM used any tantalum caps in this as those were kinda expensive between 1977 & 1984.
It has several resistors inside along with a couple flavors of diodes, a FET, a DIP IC, and other through hole components including the electrolytic capacitors.
The FET, resistors, and diodes are generally pretty stable long life parts. Resistors of this generation are generally not failure prone.
The FET might be smoked if it was shorted on a dead motor or was not properly mated against the heatsink but it's fairly stout.
The capacitors are generally your problem children. They have a finite lifespan of somewhat less than 40 years. Some vintage computer gear like my Commodore, Sinclair, and Atari collectibles have high quality electrolytic capacitors that are still in good shape. I highly doubt GM used high quality caps in this.

When you re-assemble it the back of the FET needs to make full contact with the aluminum heatsink using fresh white oxide thermal paste tho this guy seems to have gone a bit overboard with the paste.

You can see this module is a different revision with the components located differently from the above module.


The 84-91 modules can be repaired in the same fashion.

The PC boards of this vintage are usually one step up from home etched boards. If you aren't extremely careful of the heat you can and will damage them by de-laminating the copper traces from the circuit board. Even the new boards like the climate control, radio, and instrument cluster in my 2005 that look like high grade professional boards are fairly cheaply built boards that thermal damage very easily.

The wiper delay boards can be repaired by a competent electronics tech with the proper tools.
I no longer have a 78-82 test bed truck so it'd be a Hail Mary for me. One of those " I replaced the caps, tested all discretes & replaced out of spec parts, carefully cleaned the card edge contacts on the PC board, sprayed with Deoxit D5, and re-assembled with the proper paste. " kinda thing.
I'd be replacing the capacitors, checking the other components, and replacing the out of spec parts with no way to final test the module after the repair. I really don't like shipping stuff back that I haven't been able to test.

I would be very interested in getting my hands on a dead one to reverse engineer the circuit board.

[36chevy]

Wow...thank you for the great info. I can't believe they would reproduce the switch but not the Module?


I assume even if the Module is shot we can still manually use our wipers. I assume most people don't even know there is a delay function?

When you had the ability to test it in a truck were you repairing them for forum guys?

[hatzie]

Originally Posted by 36chevy

Wow...thank you for the great info. I can't believe they would reproduce the switch but not the Module?

I assume even if the Module is shot we can still manually use our wipers. I assume most people don't even know there is a delay function?

When you had the ability to test it in a truck were you repairing them for forum guys?

You can install a regular wiper switch in the dash and plug the harness into the switch instead of into the module.
It may work just fine in Hi and Lo even with the pulse setup.

Before I sold my interest in my company and retired I did board level repairs of surface mount and through hole components on my companies' embedded control systems. I liked getting my hands dirty. I still have my personal electronics bench setup.
I work on antique radios and antique lab equipment. One of my several hobbies.
I haven't repaired automotive stuff for the public.

I repaired the wiper pulse modules in my 78 & 85 trucks and I've done some cluster and electronic HVAC control repairs for friends. The 85 & 78 wiper modules failures were dead capacitors.

I should've reverse engineered the module from the 78 but I didn't.

The discrete components are likely all still available. The transistors can be a wild card but the other parts are common and easy to source. Even the Integrated circuit is likely a common enough part. Likely everything outside of the capacitors are just fine.

[Hammered 77]

Hatzie, what's the likely hood of a module from 78-82 Corvette or Camaro working in our trucks?

Rick

[Dead Parrot]

Don't know about the module but the intermittent switch in my 79 Camaro looked like the one 37chevy posted and GM often used the same parts across many lines of vehicles.

[hatzie]

Originally Posted by Hammered 77

Hatzie, what's the likely hood of a module from 78-82 Corvette or Camaro working in our trucks?

Rick

If it plugs in it'll likely work.
You're likely to run into the same old "dried out" electrolytic capacitor issue as the one you have.

They aren't difficult to replace but I wouldn't do it with a WalMart 25W or 40W iron and a solder sucker or braid. You need better thermal control.

Here's a commentary about electrolytic caps. https://silentadmin.gsans.com/my-lib...pacitors-fail/
Here's Dave Jones tutorial about Capacitors. He goes into electrolytics and how they fail and why EEs still use them with their known issues.

http://www.youtube.com/watch?v=xlvqUts9H9c

Get good name brand Rubycon or Nichicon electrolytics rated for as many hours of runtime as you can get. Panasonic are made by Matsu****a now and I won't use them. ***EDIT. I guess the board figures i was cussing and not typing a Japanese manufacturers name.
You want the same or slightly higher voltage rated, same or higher thermal rating, with the same capacitance. Modern caps are generally smaller than the caps from the 70's & 80's with the same ratings as the old ones.
Electrolytics are polarity sensitive. These PC boards have no silkscreen so you'll want to carefully replace the caps one at a time. I mark the negative leg of the capacitor on the PC board with a sharpie so I can assemble the new part in the proper + to - orientation.

If you install an electrolytic cap in reverse polarity you'll get a big POP - BANG when the power is applied to the cap. It makes a nasty mess. Tantalums catch fire so they tend to be very exciting too.

Not that I've installed either type in reverse polarity... I've just heard about it.
I am very careful but honestly it's only a question of when you'll screw up and have to clean up a mess & install a replacement cap in the proper polarity orientation.

I don't completely trust the silkscreens anymore either. I repaired a dodgy power supply on my Tek 2465A scope and got a nasty surprise. I got a big POP-BANG when I plugged it in and switched on the power strip after replacing a raft of capacitors.
The exploded cap was marked for the wrong polarity on the silkscreen. It was obvious what leg was attached to the output ground plane when I checked it with a meter. The hole for that leg was not marked properly. That was an eye opener.
Thankfully I hadn't plugged in the output for my smoke test.
To add insult to injury the Technician Manual schematic and parts list was incorrect as well. I'm not sure whether this was a manufacturing update that didn't make it into the manual or I have the manual for an earlier or later minor revision of that scope or someone played swaptronics with the power supply over the last two or three decades. All equally plausible. My manual now has notes in pencil.

[Hammered 77]

Thanks for the info, a lot there to digest before I decide whether to crack one open. I have a corvette module on the way and I'm looking at a truck module so I can see if they interchange. I'll also have to pick up a wiper motor since mine is a 77.

[hatzie]

IIRC the pre '78 dash needs to be massaged to fit the later wiper switch but that's the least of your worries here.

Download the wiring manuals and look at the wiper wiring.

You will have to install a 1978 wiper switch plug on the dash harness and new motor plugs in the engine bay.
To add insult to injury many of the plug shells are obsolete.

In the cab.

• The 1977 wiper motor handles parking internally. The 1977 wiper switch has five Male Delphi Packard 56 terminals with a special five position plug part # 8917319
  
• The 1978 wiper motor has two additional wires that handle the park function. One of these wires goes back to the switch and is grounded in the OFF position. 1978 has a six position card edge connector #12004706. This connector is the same as the connector on the delay box. The additional wire is ground for the Park function when the wiper switch is in the OFF position.

In the engine compartment. The 1977 wiper motor used Packard 56 plugs vs the 1978 wiper motor uses PAK CON II plugs. Some, if not all, of these plugs are obsolete so you'll need to liberate them from a GM car or truck of the right age. I'd look over cars since they aren't as popular as the trucks.

• 1977 had two Packard 56 plugs. 2965077 and 2977646
• 1978 has three Pak Con II plugs. 8917544, 12004622, and 8917548

You'll need to branch the LOW speed wire and route the new branch wire to one PARK switch terminal on the motor. The wiring diagram shows this branch at the bulkhead plug. I would do this at the wiper motor as it's more accessible.

You'll have to add the circuit 97 wire from the wiper switch plug to the bulkhead plug and out to the other park switch terminal on the motor.

If you don't have the tooling and experience to install new terminals on wires and insert them into the harness I would find a 1978-82 truck donor to liberate the wiper wiring from.
You can extract the Packard 56 terminals from the bulkhead plug and carefully open the wiring wrap to separate the wiper wires from the vehicle harness in the engine bay and inside the cab. At least an hour of entertainment.

[GOPAPA]

I bought a brand new 1973 Chevy truck and my wiper relay went out right away ..took it in to the dealer and got another put in,, same thing ,,the wipers would come on when ever they felt like it ,,,got another one put in and it went south too and a friend had the same problem with his new 73 ,,

So I skipped trying another new one and wired a toggle switch under the edge of my dash
Sold the truck in 1979 ,with toggle switch still in it..

[hatzie]

1973-1991 CK trucks didn't have a wiper relay. I'm not sure what relay the dealership techs were replacing on your truck but it wasn't a wiper relay.
1973-1976 CK trucks didn't have intermittent wipers.
1977 had a very rare one year only orphan intermittent wiper control system.
The various intermittent wiper system control boards from 1978-1991 used Field Effect Transistors, not a relay, to control the motor.