Chevy And GMC Truck 


Here is a handy list of all the bulbs and fuses on a typical Chevy/GMC truck.

Much of this bulb info, and other info applies to P and G model Chevy/GMC vans too.

LAMP AND BULB DATA (From my 1977 GM Factory Service Manual)

DOME LAMPS; CAB 1 1004 15 CP
Suburban and Utility 1 211-2 12 CP
Generator indicator lamp 1 168 3 CP
Instrument Cluster lamps^ 5 168 3 CP
Headlamp Beam indicator lamp 1 168 3 CP
Lamp assembly - Tail &Stop lamp 2 1157 3 -32 CP
License lamp~ 1 67 4 CP
Directional Signal (front marker lamps) 2 1157 3-32
Head Lamps 2 6014 50-60 W
Temperature Indicator lamp 1 168 3 CP
Clearance and Marker lamps 4 168 3 CP
Roof Marker lamps 5 194 2CP
Brake warning indicator 1 168 3 CP
Transmission Control (auto) 1 1445 0.7 CP
Backing lamp (reverse lights) 2 1156 32CP
Heater A/C 1 161 1 CP
Cargo lamp 1 1142 21 CP
Cruise Control lamp 1 53 1 CP
Courtesy lamp 1 1003 15 CP
Windshield Wiper switch 1 161 1 CP
Clock 1 168 3 CP
Rear Identification` 10 1895 2 CP
Under hood lamp 1 93 15 CP
Seat Belt warning 1 168 3 CP
Cargo/dome lamp 2 211-2 12 CP
Four Wheel Drive 1 168 3 CP
Oil Pressure Indicator lamp 1 168 3 CP
* On CA, KA 10-35 instrument clusters only
^ 3 lamps used on instrument cluster on models without gauges
~ 2 lamps used with step bumper and on P models
` On Wideside Pickups
All headlamps are sealed beam 50 watt low beam, 60 watt high beam.

Heater, Front A/C, Generator Warning Lamp 20 Amp
Idle Stop Solenoid, Aux. Battery, Radio, Time Delay Relay, Emission Control Solenoid, Transmission Downshift (M40) 15 Amp
Cigarette Lighter, Clock, Dome Lamp, Cargo Lamp 20 Amp
Fuel gauge, Brake Warning Lamp, Temperature Warning Lamp, Oil Pressure Warning Lamp 4 Amp
Courtesy Lamp, Roof Marker Lamp, License Plate Lamp, Parking Lamp, Side Marker Lamp, Tail Lamp, Clearance Lamp 20 Amp
Directional Signal Indicator Lamp, Stop Lamp, Traffic Hazzard 15 Amp
Instrument Cluster Lamp, Heater Dial Lamp, Radio Dial Lamp, Cruise Control Lamp, Windshield Wiper Switch Lamp 4 Amp
Windshield Wiper/Washer 25 Amp
Cruise Control. Rear Window Aux., Fuel tank, Tachometer, Back-up Lamp, Directional Signal Indicator Lamp, Directional Signal Lamp, Headlamp Buzzer 15 Amp

The truck's wiring is protected from short circuits by fuses, breakers, and fusible thermal links. The above table shows what amperage fuse should be used, with each respective circuit. In a pinch, a lower amperage fuse can be used to replace a higher amperage fuse. NEVER replace a fuse with a higher amperage fuse. SEVERE wiring damage can occur.
In-line fuses are located in the auxiliary heater circuits, under hood lamp, and front and rear A/C circuits.
Circuit breakers
Headlamp and parking lamp circuit Amps: 15, Location: light switch
Tailgate window motor Amps: 30, Location: under dash
In addition to a fuse, the Headlamp circuits are protected by the Circuit Breaker in the light switch. An electrical overload on the breaker will cause the lights to go on and off, or in some cases to remain off. The windshield wiper motor is also protected by a circuit breaker. If the motor overheats, due to overloading caused by heavy snow, etc., the wipers will remain stopped until the motor cools.
The following wiring harnesses are protected by a "fusible link" which is a special wire incorporated in the circuits:

Should an electrical overload occur, this wire will fail (burn) and prevent major damage to the harness.


Wiring Resources

Fuse Box Diagrams

A well kept secret...............For Automotive Literature it is hard to beat E Bay! GM Factory Service Manuals include full detailed instructions for replacing body panels. Every nut bolt and screw location, torque specs, and a ton more. These books are 2" thick, and often include full wiring diagrams too! Get over to E Bay!

  Click here for eBay Motors!  E Bay Motors - I have gotten many manuals there. Most recently, I picked up a GM 1982 Light Duty Truck Factory Service Manual, which includes a full wiring diagram. I won the bid for $17.00. Back in 1992, at a local swap meet, I paid $30 for the same GM factory Service manual for my 77. The older manuals didn't include wiring. I currently have a bid in myself on a 1977 GM Factory Wiring Manual. The bid is currently $10. I just also won a bid on a 1977 GM Dealer Album. It includes all pricing for all 1977 Chevrolet vehicles, the cost of all options, all the separate optional equipment catalogs (and believe me there are lots) even a brochure for the Blazer Chalet. There are paint chips, and fabric samples. It is jam packed with info. Forget Chilton's, forget Haynes, what you really need, is the GM Factory Service Manual for your GM vehicle. You can also find truck parts as well.

Factory Service Manuals!

GM Light Duty Truck Service Manuals cover the following models: C/10, C/20, C/30, K/10, K/20, K/30, P/10, P/20, P/30. (C= 2wd pickups, cab n' chassis, and Blazer / Suburban, K= 4wd pickups, cab n' chassis, and Blazer / Suburban, and the P model line is Chevy Vans. GM considers anything 1 ton or under to be a "Light Duty" vehicle.

So if you plan on restoring a car or truck, get your hands on a factory service manual, you will not be disappointed!

Click On A Book

These are the REAL books you NEED and eBay has them.


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