Check the cabin power panel first under the dashboard on the driver side, since most electrical faults in this model are tied to interior circuits such as lighting, radio, and wipers. Use a test light or multimeter to verify power on both sides of each slot before removing any component.
This vehicle uses blade-type links with rated amperage from 5A to 30A, each assigned to a specific system. A mismatch in rating can lead to wiring damage, so always match the number printed on the original piece. Common trouble points include the accessory circuit, heater blower supply, and turn signal relay feed.
Under the hood, a secondary panel protects higher-load systems like cooling fans and ignition. Corrosion around contacts is frequent due to heat and moisture, so inspect terminals closely and clean them with electrical contact cleaner if resistance is detected. Keeping a clear reference of circuit assignments reduces guesswork and speeds up fault tracing.
1991 GMC Jimmy Fuse Diagram with Fuse Box Layout and Circuit Details
Locate the interior panel beneath the driver side dash and match each slot to its assigned circuit using the labeling on the cover or service manual. This allows quick identification of which circuit protects systems like radio, brake lights, or windshield wipers.
The cabin block typically includes low to mid amperage inserts. Common assignments include:
- 10A – interior lighting and dashboard illumination
- 15A – audio system and cigarette lighter
- 20A – wiper motor and washer pump
- 25A–30A – heater blower motor circuit
Check both sides of each connector with a test light; power should be present on both terminals when the link is intact. A reading on only one side indicates a failed component that must be replaced with the same rating.
Under the hood, a separate power distribution block handles high-load circuits. These include:
- Cooling fan relay supply
- Ignition system feed
- Headlight circuit protection
- Charging system connection
Heat exposure in the engine bay often leads to worn contacts, so inspect for discoloration or melting around terminals. Replace damaged holders and clean contacts to maintain stable current flow across all protected lines.
Fuse Box Location in 1991 GMC Jimmy Under Dash and Engine Bay
Check beneath the driver side dashboard panel first, just left of the steering column, where the interior electrical block is mounted behind a plastic cover. Remove the cover by hand; no tools are usually required.
This cabin unit sits above the kick panel and is slightly recessed. Use a flashlight to clearly see slot labels and wire colors. Limited space makes angled access necessary, so a compact tester is recommended.
Look for a rectangular plastic housing with multiple blade connectors arranged in rows. Each position corresponds to a specific system such as brake lights, radio, or turn signals.
Interior Panel Access Tips
To avoid damage while working in tight space:
- Move the driver seat fully backward
- Lower your head below steering wheel level
- Use a mirror for hard-to-see markings
Under the hood, the second power distribution block is located near the battery on the driver side. It is enclosed in a black plastic case with a snap-on lid designed to protect high-current circuits.
Release the retaining clips and lift the cover straight up to access relays and higher-rated links connected to systems like ignition and cooling fans.
This engine bay unit handles heavier electrical loads, so connections are thicker and more widely spaced compared to the interior panel.
Engine Bay Block Identification
Key visual features include:
- Position next to battery or fender well
- Heavier gauge wiring harnesses
- Presence of relays alongside protective elements
Check for moisture or dirt inside the housing, as exposure can lead to poor contact and intermittent power loss across major vehicle systems.