I've needed to replace my brake light bulb on the driver side of my 93 LS400 several times in the last year. Always the same bulb. I just noticed that this time there is a moisture build-up inside the tail light assembly and some minor corrosion in the blown bulb socket beginning to form. I was told that the seal around the assembly is probably not sealing tightly and that I should use dielectric grease in the light sockets and put a bead of clear RTV silicone around the tail light assembly before reinstalling the assembly.

Has this happened to anyone else and does anyone think I should not use the dielectric grease in the socket and/or seal the assembly as suggested?

 

There should be a rubber sealing ring on the bulb holder so make sure that is fitted, if there are no obvious cracks in the cluster it wouldn't hurt to apply some clear silicone around the seams or buy a decent used replacement from a breaker.
Also check in the spare wheel well for water ingress.

 

The rubber sealing rings are there as you suggested. I cannot see any indication of a crack or bad seal anywhere and no indication of moisture in the trunk. What do you think about the dielectric grease. I know that there is a gease substance on some of the electrical connectors in the engine compartment. I presume that was factory installed dielectric grease.

 

Applying the dielectric grease wouldn't do any harm, it's all over the place in electrical connections as you mention but you will still need to find the cause of the moisture getting in.

 

i had this happen and i just used clear rtv and sealed around the whole light..it fixed the issue

 

Steve2006 and Python thanks for your comments. I will proceed with the grease and the silicone sealant around the entire assembly. Thanks again.

 

grease for the connections...rtv to seal

 

I put the dielectric grease on the connections and sealed the edges of the tail light assembly with silicone sealant. It’s been about a week and we have had an abundance of rain since then and no water issues. I think the issue is resolved. Thanks for everyone’s help.