Fuel Filter Base - Restriction Switch Elimination

90chevy08
GMC NUMBER: 90-6C-45

GROUP: 6C Engine Fuel

DATE: April, 1990

CORPORATE
NUMBER: 066303
SUBJECT: ELIMINATION OF RESTRICTION SWITCH FROM DIESEL ENGINE FUEL FILTER BASE

MODELS: 1982-1990 LIGHT DUTY TRUCKS EQUIPPED WITH 6.2 L ENGINES (VIN CODES C, J)

Figure 1 - Current Configuration (SOP 1990) w/o Restriction Switch:

Figure 2 - Former Configuration (Pre-1990) w/Restriction Switch IT.13:

Beginning with the start of production for all models listed above, the vehicles were built with a fuel filter base that no longer contains a restriction switch (vacuum sensor). It can be seen that the restriction switch labeled as number 13 in Figure 2 has been deleted from the present configuration as shown in Figure 1. The model 80 fuel filter base has the same exterior form.
The Service Part number has not changed. Therefore, fuel filter bases ordered through GMSPO will not have a restriction switch. When installing a new fuel filter base on a 1989 or earlier model the restriction switch connector from the wiring harness will not be connected to the fuel filter base. The unused connector should be taped back to the wiring harness to prevent damage.