Got some dim side and back lights on the XJ

All the exterior lights on the XJ have gone dim over the years and I'm wondering if there's anything I can do to get them brighter short of upgrading to a newer type bulb. Everythings running fine electrically, but just the exterior bulbs seem dim themselves, and since the lenses and reflectors are 21 yrs old maybe they're part of the problem too?

At one point my headlight output was just bad so I upgraded the whole harness to something from LMC and some E Pal lenses. Now they come right off the battery through some relays and illuminate so much better.

Should I be looking to do something like that with the rest of my lights?

With dim lights the first thing i would is clean all light sockets and check and clean grounds and chassis grounds

Yeah, grab a meter and measure voltage on both sides of the bulbs. You can buy replacement lenses pretty cheap on eBay. I just bought a set not too long ago for $20 shipped for an 89. They're not super high quality, but they're clear and not broken like the old ones. I never could find the taillights for the MJ under $100 each, so I might trying polishing those instead.