What is up with GMT400 Driver's Tail Lights?!

Kinja'd!!! by "Akio Ohtori - RIP Oppo" (akioohtori)
Published 04/17/2017 at 23:24

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STARS: 5


On a trip to our local pick-a-part for some Saab stuff , I had a thought: I should pick up a control board for my Yukon’s driver’s side tail light, as mine is going wrong. And then I discovered that apparently I am not the only one looking for one!

Kinja'd!!!

Of the 17 compatible vehicles I found just by wandering around, only two had the driver’s tail lamp assembly still in the car, both of which didn’t look worth pulling. Don’t believe me?

Kinja'd!!!

After the first five or so, I started taking pictures. Most of them had the passenger lens and board still in place, which is even more strange.

I just... I have no words for what is happening here. I guess I’m not the only one having problems with these.

Kinja'd!!!


Replies (13)

Kinja'd!!! "ITA97, now with more Jag @ opposite-lock.com" (ita97)
04/17/2017 at 23:30, STARS: 3

I’ve replaced both boards (actually, I just did the entire assembly) on my escalade over the years when they started having problems. Rockauto has entire assemblies for cheap.

Kinja'd!!! "Akio Ohtori - RIP Oppo" (akioohtori)
04/17/2017 at 23:32, STARS: 0

Yup, Amazon too. It was a “while I was here” thing that turned into a “WTF?”

Kinja'd!!! "Urambo Tauro" (urambotauro)
04/17/2017 at 23:39, STARS: 1

As the owner of a 1995 C2500, I was already aware of this being a super-common issue, but I’m honestly just as stumped as you are. Just what is the exact failure point here? Do they all have weak solder joints or something? Are they extra-susceptible to corrosion? How hard can it be to make a board that lasts?

Kinja'd!!! "littleBenny" (zsssssssssssa)
04/18/2017 at 00:03, STARS: 0

Drivers side door panels and the outside mirrors are items that I’ve never been able to find intact at junkyards around here. Taillights are in high demand due to faulty wiring that causes them to burn up.

Kinja'd!!! "Highlander-Datsuns are Forever" (jamesbowland)
04/18/2017 at 00:05, STARS: 3

It’s a left conspiracy.

Kinja'd!!! "shop-teacher" (shop-teacher)
04/18/2017 at 02:39, STARS: 0

My dad owned two GMT-400's from new, an ‘88 and a ‘95. Believe it or not, the problematic ones that fail so quickly, are redesigned parts that are actually better that they were originally. The boards in my dad’s ‘88 both went bad within a few years.

Kinja'd!!! "Tristan" (casselts)
04/18/2017 at 03:03, STARS: 2

I had no idea this was an issue... So, naturally, mine will fail tomorrow.

Kinja'd!!! "avalonian" (avalonain19)
04/18/2017 at 08:50, STARS: 0

Whenever I go to a junkyard looking for a part on my Avalon, every right passenger door is always missing, so that prevents me from changing the interior wood trim and grabbing a new passenger window. Especially because every other door is there with all its panels except the left one!

Kinja'd!!! "cletus44 aka Clayton Seams" (cletus44)
04/18/2017 at 09:05, STARS: 0

It’s an odd phenomenon and I don’t know why. I’ve replaced my driver’s side bulbs twice in my 17 yr ownership but have never even removed the passenger side housing.

Kinja'd!!! "Dave the car guy , still here" (a3dave)
04/18/2017 at 11:04, STARS: 3

Kinja'd!!!

Circuit board on back of lamps corrodes easily. The aftermarket ones usually last about 1-2 yrs in the Midwest where road salt is used. The earlier factory ones 3-7 depending on car wash habits. The later factory ones lasted even longer. The bulb contact areas also have melting issue on some if the snap in bulbs have a plastic tab where the wire wraps over it. If you find ones with a glass base they seldom have a problem. Have had friends buy the cheap ones and spray ignition waterproofing spray on the panel to seal them. Tape over the sockets beforehand. Its a fair DIY solution but not foolproof.

The earliest versions of these lamps in 1988 had old style metal base bayonet bulbs and had corrosion issues as well. Many got changed over to snap in bulbs and still had problems.

Kinja'd!!! "Urambo Tauro" (urambotauro)
04/18/2017 at 11:33, STARS: 1

So did the boards not have any kind of conformal coating from the factory? I wonder if the housings might also be particularly bad at venting moisture out.

I’ve had mine open to change bulbs, but I never took a real close look at the design. The one thing that I did notice, and I’m not sure if it’s OEM, is that the bulb contacts had a yellow clay-like “grease” that seemed very dry. I had to pick it out in chunks before putting it back together with dielectric grease.

Kinja'd!!! "Dave the car guy , still here" (a3dave)
04/18/2017 at 12:35, STARS: 1

No coating from factory on either factory or aftermarket. The units weren’t sealed enough to keep out all moisture. Some of the cheaper aftermarket had such bad grade of steel strips for contacts that they rusted apart. The circuit strip on all of them are usually partially concealed under some plastic but not enough to protect fully. All the aftermarkets I’ve seen look to be slightly different from OE depending on brand to avoid patent infringement.

Kinja'd!!! "Duck Duck Grey Duck FTMFW!" (theduckduck)
04/18/2017 at 15:07, STARS: 1

This explains the issues I am having with my 97' K1500. It’s the driver’s side. I at least know what to deal with when it shits out again.