1984-1989 C4 Fuel Pump, Transmission Overdrive Electric, Skip Shift Relay - OEM Number(s) (14078915)
Restore proper fuel pump and transmission relay operation with an OE-style relay designed for multiple C4 Corvette functions.
This Corvette relay is designed for 1984-1989 C4 applications and serves multiple factory functions depending on model year and transmission configuration. It is commonly used as the fuel pump relay on 1984-1987 Corvettes, the 4+3 overdrive relay on manual transmission models, and the 1-4 skip shift relay on 1989 applications.
A failed relay can prevent the fuel pump from priming, causing a no-start condition, or disable overdrive and skip shift functions. This direct replacement relay restores proper electrical operation and OE-style functionality.
The relay is located at the rear of the engine compartment, mounted near the firewall and wiper motor area for easy access and replacement.
Fits the Following Corvette Models:
C4 Coupes and Convertibles:
• 1984-1987 Fuel Pump Relay
• 1984-1987 4+3 Overdrive Relay
• 1989 1-4 Skip Shift Relay
Features / Benefits:
• Multi-function relay for 1984-1989 C4 Corvette
• Used as fuel pump relay on 1984-1987 models
• Used as 4+3 overdrive relay on manual transmission applications
• Used as 1989 1-4 skip shift relay
• Helps restore proper fuel pump priming and starting operation
• Restores overdrive and skip shift electrical control functions
• OE-style direct replacement
• Easy installation at rear engine compartment location
• GM reference part number: 14078915
Material / Finish:
Factory-style electrical relay construction designed for dependable switching performance and durability.
Because Details Matter
Electrical relays are critical to fuel delivery and transmission control systems. Replacing a failed relay restores proper operation and helps maintain the reliability and drivability expected from your C4 Corvette.
Also known under these part numbers: (For reference only)
- 036666283372
- 14078915
- 212307
- 48910
- R671
How to Install 1984-1989 Corvette Fuel Pump, Transmission Overdrive Electric & Skip Shift Relay
Fits:
Mid America Motorworks Technical Tip
MAM Part Number: 611072
OEM Reference Number: 14078915
Mid America Motorworks provides restoration and maintenance parts for Corvette enthusiasts. Use the following instructions as a general guide for replacing the fuel pump relay, transmission overdrive relay, or skip shift relay on your 1984-1989 C4 Corvette.
Relay Installation Procedure
Step 1 – Open Hood and Locate Relay Assembly
Open the hood and locate the relay assembly mounted near the windshield wiper motor.
Important:
- Manual transmission vehicles may have two relays mounted together with the same part number.
- Relays are mounted to two small brackets using 10mm nuts.
- Brackets are attached to the firewall using rubber grommets with threaded sleeves.
Step 2 – Identify Correct Relay
Before removal, identify which relay is being replaced by verifying wire colors in the connector.
Overdrive / Skip Shift Relay Wire Identification
| Cavity |
Wire Color |
Function |
| A |
Dark Green |
To Transmission |
| B |
Tan/Black |
To ECM |
| C |
Pink/Black |
To Gauge Fuse, 12V Ignition On |
| D |
Brown |
To ALDL, Pin F |
| E |
Pink/Black |
To Gauge Fuse, 12V Ignition On |
Fuel Pump Relay Wire Identification
| Cavity |
Wire Color |
Function |
| A |
Red |
To Oil Pressure Switch |
| B |
Black |
Ground to Engine |
| C |
Dark Green/White |
To ECM, Cavity A1 |
| D |
Red |
To ALDL, Pin G |
| E |
Orange |
12V Constant to Fuse Link H |
Step 3 – Remove Existing Relay
- Disconnect electrical connector from relay.
- Remove mounting hardware securing relay bracket.
- Carefully remove relay assembly from firewall bracket.
Step 4 – Install New Relay
- Position replacement relay onto mounting bracket.
- Install mounting hardware and tighten securely.
- Reconnect electrical connector ensuring full engagement and locking tab retention.
Step 5 – Verify Installation
- Start vehicle and verify proper operation.
- Confirm fuel pump operation and/or skip shift/overdrive function depending on application.
- Inspect wiring connectors for secure fitment and proper routing.
Important Installation Notes
- Always verify connector wire colors before replacing relays.
- Manual transmission vehicles may contain both fuel pump and overdrive relays mounted together.
- Inspect relay connectors for corrosion or heat damage during service.
- Verify firewall mounting grommets are secure before reinstalling relay assembly.