Cargo Lamp Gasket?
 

'98 Silverado XCab. The gasket is shot for my rear cargo area lamp and water leaks inside the cab when it rains (rarely) or go thru the carwash (weekly). I also run the Sirius antenna cable under the housing and thru the hole for the lamp wiring so a stock replacement gasket probably wouldn't work. Any homegrown gasket ideas or should I just run a bead of silicone around in and trim off the excess?

Best bet is clear silicone. Run a bead and have a cup of water to wet your finger and smooth out the bead. If done right, no trimming is needed.

Thanks for the info - I'll let you know how it goes.

Good deal.

finally had a chance to get the truck washed and NO LEAKS! I had some hi-temp gasket maker left over from the water pump replacement. I spread a bead on both sides of the existing gasket and all is well!

Sweet!