imbalance of some kind in your truck's chakras (truckras) need to use switch cleaner on bulb contacts as well as lights fuses. use a better brand bulb. otherwise consult nostr:npub1aj3rzhh4p4ngxpfg0s0ts4tcgx0eavxwmdmrnmvn8etcwmxfc58qjzhxuc for rat eaten wires.