77 wiper switch?s

[Displaced_Txn]

so need to get my k5 inspected and need the wipers to work on it to pass safety,  the pulse board is broken and there is no replacement avaiable for it that i can find, the switch is toast as it wont move can only push it in to "wash" as i dont have a resivor currently. the switch is another part that   and all the others dont seem to sell they cover 73-74 then 78-87. can i get a switch for say a 79, locate the pulse board and use it or would i end up with it not working, and also what ive found and been told is that 77 was a first and only run year for that style switch and pulse board.

[hatzie]

The 77 pulse wiper setup is actually fairly rare.  It's different from the 78 -83 setup.  GM modified the 78 and later motor by adding an external park ground.

I'd be interested to see an actual 1977 pulse wiper switch and controller.

[Displaced_Txn]

well apparently i also have the newer style wiper motor for the older style switch and board, guess i might try to find a 78-83 board and switch and give it a whirl and

broken pulse board.


switch front and rear

[hatzie]

Through hole discrete electronics.  I see Resistors, Electrolytic and Tantalum Capacitors, at least one diode, and an IC... with a board mounted relay. 
I'd be interested in acquiring the dead control board and dead switch.  It'd be a shame for them to just get heaved. 
Once in hand a complete schematic of that board shouldn't be difficult to generate.

[hatzie]

Some interesting reading on delay wipers...
http://www.rowand.net/Shop/Tech/DelayWipers.htm

[Displaced_Txn]

well got a wiper switch, relay board, motor out of an 82 i think, now comes the fun part of trying to wire it all up

[hatzie]

I would spend the time to liberate the wiper wiring from the donor. 

I believe the 73-77 motors used Packard 56 connectors.  There's one more wire in the wiper harness starting in 1978.  I know the 78 and newer motors use Pack-Con II connectors.  85 and newer used Packard 56 on the tank mounted washer.
You can remove the engine bay wiper wiring fairly easily.  The big square bulkhead plug end are Packard 56 Male terminals.  They are very easy to remove and insert. 
The position for the, new for 1978, wire #97 is shown present and empty in the 1977 bulkhead plug wiring diagram.

GM also went from Packard 56 to Pack-Con II on the switch in 1978... 
You can liberate the 1978-1983 cab wiper switch wiring and plug by removing five female terminals from the bulkhead plug with a 00 flat screwdriver.  The only wire that doesn't go through the firewall bulkhead plug is the Black Ground wire.  Just leave a 6" - 12" black tail on the switch plug to solder to the black ground wire in your 1977. 

Packard 56 disassembly instructions are on page 26 & 27 of this STG manual.  http://www.mediafire.com/download/yb3hd53fgg3mmmc/GM_STG_18001_02_VA_Wiring_Assembly_Repairs.pdf
If you need them... the Pack-Con II instructions are on page 17.
Some more info in this SuperChevy Article.  http://www.superchevy.com/how-to/interior/1506-understanding-gms-most-common-plug-options/

Attached are the 1977 & 1978 bulkhead plug pinouts from the wiring diagrams.  Wipers are wires 91-94 & 97.

[Displaced_Txn]

got switch wired up, pulse board wired, and motor wired up and slow speed, slower speed and no pulse. so guess i need a new motor for better speed and to figure out the no high speed, and park

[Displaced_Txn]

looks like in the picture the wire from 5 runs to 2 so pulse would be a double ground? For some reason im over thinking this to much, had the 5 plug ran to power so gonna grab a new fuse in the am and rewire and recheck it,  really need to switch to a more common fuse block than the glass fuses.

[hatzie]

looks like in the picture the wire from 5 runs to 2 so pulse would be a double ground? For some reason im over thinking this to much, had the 5 plug ran to power so gonna grab a new fuse in the am and rewire and recheck it,  really need to switch to a more common fuse block than the glass fuses.

Liberate an ATC panel and cab harness from a 79-82...  79 & 80 are preferrable but 81 & 82 will fit without a lot of drama.

Sent from my SM-P605V using Tapatalk

[Displaced_Txn]

got the wiring fixed , swapped the fuse from the radio/ engine stop holder to washers, and have washers, considering before i just had slower than a slug and only worked on the wash setting. With thanks to  hatzle on the bulkhead pin out, really dont see how all the 77 wiper threads ive read on various forums just gave up after doing the whole swap.