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**hatzie** · 10-14-2021, 11:26 AM

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.

10-14-2021, 11:26 AM	#11
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,915	Re: 1982 Whiper Delay Module 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. __________________ 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; 10-14-2021 at 05:35 PM.