The old GMC pickup in these photos arrived at the shop for a pair of door concerns. The right side door would not open from the inside. This is a common problem with these old trucks where the interior handle simply breaks after 30 years of fleet duty use. I've replaced many of these handle assemblies over the years, so much so that we actually keep the parts in stock.

The second concern was that the driver's door would not open from the outside. This is also something I see with regularity and usually involves a broken exterior handle assembly, (we keep these in stock also). However, this handle had recently been replaced. So I'll have to do some investigating to see what happened.

But first, I couldn't help but notice this creative wiring.

It looks like someone installed, (or tried to install), an aftermarket radio.

A speaker was installed behind the seat.

Connecting the two was this . . . interesting . . . wiring harness.

I have no idea if any of this works, and really don't want to know, to be honest. Anyways, back to the topic at hand.

Accessing the door latch and linkage rods requires the removal of the door trim panel and the door access panel. GM pickups from this era actually have a pretty decent design where the window regulator is attached to a large access panel that can be removed from the door which provides a lot of working room.

I removed the recently replaced exterior door handle assembly. Normally, this involves disconnecting the linkage rods that go to the latch and lock cylinder and unbolting the handle assembly from the door. Two things immediately made themselves known.

First, I discovered that the door lock cylinder had already fallen out of its circular housing seen in the photo above. Supplies of factory GM replacement parts of this nature dried up ages ago. But plenty of replacements are available via the aftermarket, in this case, Dorman. And while aftermarket parts work, they aren't factory parts. It's hard to explain. But getting an aftermarket part to fit and function properly can sometimes involve more than just bolting it in place. In this case, I'll have to engineer a fix for keeping the lock cylinder in place. But that shouldn't have an effect on handle operation.

This lead me to discovery #2. Handle operation is controlled by a linkage rod that is supposed to be attached to the arm on the left side of the handle assembly in the photo above, which it wasn't. That rod not being connected explains the handle inop. concern. So where is the linkage rod ?

The door lock cylinder was still in the door and connected to its linkage rod, like it should be. The front face of it had fallen off and was laying in the bottom of the door. So I'll have to repair this as well.

I had to remove the door latch assembly to find the missing door handle linkage rod. The 180 degree bend seen in the photo above definitely should not be there !

The linkage rod should be a straight piece that connects to the arm on the door handle assembly to the door latch. But since the latch sits below the door handle, a 180 degree bend just won't work. Not only do I not have an explanation for how this happened, I can't imagine a scenario where this would be possible.

Since the supply of linkage rods probably dried up before the handles, I started measuring and bending the rod hoping to get it back to normal. I repaired the door lock cylinder, engineered a fix for keeping it in the handle, and reassembled everything. I wonder how long it will last this time.