Left side brake light

2008 tacoma left side brake light bulb blows after a week or two. Any suggestions as to why?

 

Loose Socket or any other loose connections causing a spike each application .

Have you measured the voltage at the socket??

You are using the correct bulb??

Is it only the brake light filament that opens ?

 

Is there any condensation?

 

It is the bulb listed, it is only the brake side of the bulb, I haven't really dug into things yet, electrical is not my strong point but you have given me a few things to look at. I didn't notice any condensation when I changed the bulb last time. I also don't think the TRD offroad came with trailer wiring but this one has a trailer plug so there may be a splice somewhere causing problems.

 

So since you state that it is only the brake side of the bulb I would for now write off the ground since that is shared with the tail/market lights on that bulb, it is possible the ground wire has a fault and the tail/markers dont draw enough juice for them to fail but its unlikely.
Based on the haynes manual wiring diagrams the blue wire is for the power to the brake lights, the green is the tail/marker lights, and the ground is white/black. Based on said diagram the brake switch sends voltage to the driver side junction box and from there you have three wires for the three brake lights. Thus I would assume you have a problem between said junction box and the bulb socket on that BLUE wire that goes to the left brake bulb.

Please post a picture of the trailer wiring plug and we can tell you if its OEM or aftermarket, if aftermarket I would look for were it was spliced into the harness. I do not see trailer wiring specified anywhere in haynes but I will check on Alldata at work Tuesday, that will only be useful if its OEM trailer wiring of course.
I assume you do not have anything hooked up to this trailer connector as you seem unsure of it, on the off chance you do have something connected then unplug whatever it is and see if the bulb still blows.

How many times has the bulb blown? When did it start blowing? How often does it blow, ie each week, once a month? And importantly what brand are you using, I have used a few free bulbs in the past of unknown brand and had them blow out quickly, I use sylvania bulbs now and rarely have problems.

 

I got into it yesterday, the trailer plug does seem to be factory based on how it goes into the main harness, it is a round 7 pin. There were 3 splice connectors snapped into the wiring of the tail light housing and whatever was hooked to those splices had been cut off. I removed the splices and re-spliced and taped everything and replaced the bulb so all seems to be good for now.