I am reading service information and find what I am reading a bit difficult to understand. Perhaps having the actual part to look at as you do may help. It looks to me as if there is a nylon plug in the center of the plastic piece you are looking at. My information says to CAREFULLY tap the pug out using a 1/8 inch drift. This is done after moving the window to a position where you can access the pin. Reattaching the window to the regulator is even less clear. It looks a if you reattach the plastic plug and pin to the window, then slide down into the regulator. Good Luck!
I don't think the problem is your flasher. I would recommend you check all the left side turn signal bulbs buy removing them one at a time until the dash indicator goes off. Then check closely that bulb and socket for proper bulb instillation and socket damage.
Check the fluid level first. If it is OK then towing it to a repair shop is probably the next step. Please use the following link to find a repair shop near you - https://repairpal.com/directory?address=55407&car_brand_names=Chevrolet
Unless you feel the ride quality is not what is should be, I would not worry to much about changing a slightly leaking shock. It is not commonly necessary to replace the springs when the shocks are replaced unless the spring is actually part of the shop.
Is the security light on or flashing?
The tail, marker, and dash lights commonly share the same fuse. I would recommend a visual inspection of all exterior lights for water or bulb damage - don't forget the license plate lights...
This problem is commonly caused by a failed fuel level sensor inside the fuel tank. If the fuel tank is removed to replace the level sensor, I may be wise to replace the fuel pump at the same time.
The automatic transmission cooler in internal to the radiator. Coolant mixed with the transmission fluid would indicate an internal radiator leak. Replacing the radiator and then flushing the transmission fluid should correct this concern. I would not drive the vehicle with coolant in the transmission fluid, doing so could result in internal damaged to the transmission due to lack of lubrication.
It sounds like the anti-lock brakes my be activating intermittently when coming to a stop. It is possible this can occur without a fault code being stored in the ABS control module and no warning light. The only way to confirm this may be to have the problem occur with a scan tool connected in order to monitor the wheel speed sensors while the fault is occurring.
You may have a problem with on of the valve seats, this has been reported as a common problem - http://repairpal.com/worn-valve-seats-may-cause-engine-misfire-115. Performing a cylinder leakdown test may be necessary to confirm this.