Hardtop - 91 300SL - Trouble Codes

[bbrewer]

Small problem, I hope, but I have a 1991 300SL, and am having a trouble code occur whenever I install the hardtop on my car...

Both the softtop operation and the hardtop operation perform well, and I wouldn't think I have any top-related problems with either top if it wasn't for the blinking light. If I'm just putting the softtop up or down, the red light is on during operation, and off while I'm not working with the top, so no problems there.
But when I install the hardtop, the top switch light is on a solid red while the car is stationary, and a blinking red light while the car is moving..... The top seems to latch correctly, both front and rear, while both snugging it down and releasing it, yet the light indicates otherwise.

I have checked and cleared (I "think" I cleared them, they keep coming right back) the two codes, but I keep getting code #18 and code #20.
My understanding is that code #20 means the hardtop is in place with no faults, but the light also keeps indicating otherwise...

Any advice or leads on what to look at first would be much appreciated.

Thank you very much.