1. Preparation:
* Safety First: Disconnect the negative battery cable to prevent accidental shorts. Wear safety glasses.
* Gather Tools: You'll likely need a screwdriver (likely Phillips head), possibly a nut driver or socket set depending on the mounting hardware, and possibly a trim removal tool to avoid scratching the plastic.
* Examine the Mirror: Before starting, carefully inspect how the mirror is attached. Take photos if needed to aid in reassembly.
2. Removing the Old Mirror:
* Interior Access (Most Likely): On many 1990 Silverados, the mirror is attached from the inside of the door. Look for screws or bolts holding the mirror housing to the door panel.
* Removing the Door Panel: This usually involves removing screws around the edges of the door panel and carefully prying it away with trim tools. Be gentle; the panel is plastic and can break. Consult a repair manual for your specific truck model to find the location of these fasteners; they can be hidden under covers or armrests.
* Disconnect the Wiring: Once the panel is removed, you'll need to disconnect the electrical connectors for the mirror (if it's power-adjustable and/or heated). Take note of how they connect for reassembly.
* Remove the Mirror Housing: After disconnecting the wiring, remove the screws or bolts holding the mirror housing to the door. The mirror glass itself might be attached to the housing with clips or screws.
* Exterior Access (Less Likely but Possible): Some trucks might have a few exterior screws as well as interior fasteners. Check the outer edge of the mirror housing for any visible screws.
3. Installing the New Mirror:
* Reverse the Removal Process: Install the new mirror housing by reversing the removal steps. Securely attach all screws and bolts.
* Reconnect the Wiring: Carefully reconnect the electrical connectors to the new mirror (if applicable).
* Reinstall the Door Panel: Carefully snap the door panel back into place, ensuring all clips engage properly. Reinstall any screws.
4. Testing:
* Reconnect the Battery: Reconnect the negative battery cable.
* Test the Mirror: If it's a power mirror, test the adjustment and heating functions.
Important Considerations:
* Repair Manual: The most accurate and detailed instructions will be in a repair manual specific to your 1990 Chevy Silverado. These manuals are available online and at auto parts stores. This is highly recommended.
* Mirror Type: The process may vary slightly depending on whether your mirror is manual or power-adjustable/heated. Power mirrors have additional wiring connections.
* Parts: Ensure you purchase the correct replacement mirror for your specific Silverado model.
If you're uncomfortable performing this repair yourself, it's best to take your truck to a qualified mechanic. Improperly installing the mirror could lead to damage to your door panel or electrical system.
