Something you may want to try. Go to any parts store and buy some Evapo Rust. Make sure you get a gallon. In the engine compartment take your bulkhead connections loose. Get yourself a plastic container large enough for the connectors to fit in. You’ll have to loosen the cables a bit to allow The connectors to hang down. Fill the container with Evapo Rust. You’ll need something like cardboard to set the container on so it won’t spill. Take your connectors and submerge them in theEvapo Rust. Leave them submerged for 24 hours. After they have soaked take a squirt bottle of heat water and rinse out the connectors. Then blow dry. Good source for that are those cans of compressed air.
Now, you can remove the bulkhead connector from inside the car. Again repeat the procedure. Be care full not to spill any liquid on your carpet.
Once dry you’ll see the pins on the three connectors in the engine compartment clean and free of corrosion. Before putting everything back together take a q tip and dab some dialectic grease on the pins.Remember, disconnectyour battery before working on electrical.
