If the tail light is causing the battery drain, fix it first. Then see if your current battery will still function. Check ebay.

 

^^^ this. Fix the tail light if it is the root of the problem, then get your battery tested for free elsewhere. Then if the battery is still weak, replace it on your own or then push forward to get it replaced. I would not pay the $300 for a battery test/battery replacement. I mean if they are going to replace it anyhow, why even conduct the test?

I have seen some tail lights on the forums for sale recently, very reasonably priced. If you can't find one, order a tail light from either White Bear Lake or Tasca, both of which are way cheaper than the dealer quote.

 

Before you buy a new light can't you see if you can open it yourself, dry it up, and reseal it? Worse that can happen is you break it,and you buy a new light.

 

Why is a tail light 2k? Are they doing any electrical work for the short? Or is it just water causing it?

seal the tail light yourself or buy aftermarket for a fraction of the cost.

Battery may still hold a charge. Wouldn’t replace it just yet. Don’t do their fuel service

 

Without vehicle information

HINT/TIP: Put your -complete- vehicle information (year, model, cab, trim, engine, wheelbase, _x4 drive, mileage, modifications, etc., etc.) in your signature -OR- provide it in your posting(s).
.

 

why isn't this stuff covered under warranty?

 

45k miles. Bumper to bumper ends at 36k miles

 

My opinion, the problem is the dealership. Take your truck and business elsewhere. They are ripping you and other customers off. KM

 

Disconnect taillight in question, see if issues go away (connect a temporary magnetic set of tow lights if you need/want to drive safely while real taillight is disconnected)

dont ever go back to that dealer.

 

If it wasn't for this damn virus I'd be tempted to challenge this dealership and mechanic to a substantial wager about what it would take to fix the truck as long as the problem is as you describe:

""No wreck and it runs, but the alarm, flashers and lights will randomly turn on and the tailgate keeps opening on its own randomly. I was driving the other day and the truck just turned off going down the road""

There is absolutely nothing about a 2018 taillight unit related to the described problem that can't be fixed, The body module too? Nothing about this estimate adds up. But also cmd242, you should have enlightened us about your truck. All we know is you have an F650 and you haul granite slabs with it. Right? It's as good as any other assumption.