Hello Customer (name blocked for privacy)
It sounds like it may be related to the harness. I recommend to follow harness to all conectors, uncouple harness connection visually inspect both sides of connection for moisture, corrosion or other contamination, then use an ELECTRICAL spray cleaner. CRC makes a very good ELECTRICAL CONNECTOR spray make sure it s says ELECTRICAL CONNECTOR or COMPONENT on the can then use either dielectric grease or spray. This will be the easiest and fastest way to determine if connector problem or possibly harness issues.
Please get back with me to let me know. I will provide other options if doesn't work.
Thank you for asking Just Answer