For many of the notorious electrical issues in the Porsche 928 (and older cars in general), the solution is often as simple as using electrical contact cleaner. The problems frequently stem from poor or intermittent contact at connectors, fuses, and relay sockets.
⚡ Why Electrical Issues Occur in the 928
The Porsche 928 is an older, complex car, and several factors contribute to its predisposition for electrical “gremlins” (erratic or unexplained faults):
- Corrosion and Oxidation: Over time, especially with exposure to moisture and temperature changes, the metallic contact points in plugs, connectors, relay pins, and fuse ends develop a thin layer of oxidation (rust) or corrosion (e.g., green patina).
- Increased Resistance: These layers of contamination are non-conductive or highly resistive. When the electrical signal tries to flow through the dirty contact, the resistance drastically increases.
- Poor Flow: This increased resistance reduces the voltage reaching the component (e.g., a pump, light, or switch), causing it to malfunction, work intermittently, or fail completely.
- Heat Generation: High resistance also generates heat, which can further accelerate the breakdown of the contacts and surrounding plastic.
- Vibration and Wear: Connections can loosen over decades of driving and vibration, making the contact between pins and sockets unreliable. Contaminants settle into these small gaps.
- Central Electric Panel (CE Panel): The 928’s Central Electric Panel (CE), which houses the fuses and relays, is a known trouble spot. Corrosion on the fuse holders, relay sockets, and ground points can cause widespread problems.
✨ How Contact Cleaner Is the Solution
Electrical contact cleaner is a specialized solvent designed to safely and effectively remove contaminants from conductive surfaces without damaging the surrounding plastics or leaving behind a residue.
1. Dissolving Contaminants
- Solvent Action: The cleaner, typically delivered as a high-pressure aerosol spray, uses powerful, fast-evaporating solvents (like certain alcohols and hydrocarbons) to dissolve and flush away non-conductive materials such as dirt, grime, oil, grease, flux residue, and light corrosion/oxidation.
- No Residue: High-quality contact cleaners are designed to evaporate quickly and completely, leaving behind no residue that could attract new contaminants or interfere with the connection.
2. Restoring Conductivity
- By removing the insulative layer of oxidation and debris, the cleaner restores the direct, low-resistance metal-to-metal contact between the electrical surfaces (e.g., between a relay pin and its socket).
- Complete Circuit: This action allows the necessary current (amps) to flow without interruption, ensuring the component receives the correct voltage (volts) to function as intended, thus solving the “bad contact” problem.
Key Areas to Clean in a 928:
The contact cleaner solution is often applied to:
- Relay and Fuse Sockets in the Central Electric Panel.
- Ground Points (Earths): Cleaning the main chassis ground points (where multiple brown wires often converge) is crucial, as poor ground connections are a common cause of electrical faults.
- Multi-pin Connectors: Specific multi-pin connectors in the engine bay (like the T-14 connector) which are susceptible to moisture.
- Switches and Potentiometers: Cleaning the internal contacts of aging switches (like the ignition switch or power window switches) can fix intermittent operation.
⚠️ Important Safety Note
- Always disconnect the car’s battery before cleaning electrical connections.
- Ensure the cleaner is rated as safe for plastics and allow the component to dry completely before reconnecting the power, as the fluid is conductive until fully evaporated.
- Some experts also recommend a final application of a dielectric grease (which is non-conductive) to the outside of the connection housing or seals after cleaning to protect the contacts from future moisture, but this should generally not be applied directly onto the conductive contact surfaces unless specified for that type of connector.
