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**hatzie** · 11-05-2018, 02:21 PM

If your truck came with dual fuel tanks RPO NL2 will be on your SPID in the glovebox and on the build sheet stuffed into the seat springs.

There were actually three different switches used on the NL2 system.
1973-1980 will work out of the box. It's a DPDT switch with one terminal removed to key the connector.
1981-1986 will not work. It's a momentary Polarity Reversing switch that springs back to a centre off position. It's marked DEPRESS FULLY.
1987-1991 will work with some head scratching. This is a continuous Polarity Reversing switch with two ON positions and no centre OFF.

Either non-momentary switch will carry the amperage necessary to power a fuel pump.
My first choice would be the 73-80 switch.
If you have the AC Delco D7089C switch you have the polarity reversing NL2 switch that ran the TBI fuel pumps.

11-05-2018, 02:21 PM	#4
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,915	Re: tank switch in dash for tbi trucks ? If your truck came with dual fuel tanks RPO NL2 will be on your SPID in the glovebox and on the build sheet stuffed into the seat springs. There were actually three different switches used on the NL2 system. 1973-1980 will work out of the box. It's a DPDT switch with one terminal removed to key the connector. 1981-1986 will not work. It's a momentary Polarity Reversing switch that springs back to a centre off position. It's marked DEPRESS FULLY. 1987-1991 will work with some head scratching. This is a continuous Polarity Reversing switch with two ON positions and no centre OFF. Either non-momentary switch will carry the amperage necessary to power a fuel pump. My first choice would be the 73-80 switch. If you have the AC Delco D7089C switch you have the polarity reversing NL2 switch that ran the TBI fuel pumps. __________________ 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; 11-05-2018 at 02:37 PM.