Can you elaborate a bit on what's happening. When you say not working all the time...how often & how are they not working (i.e. come on 1/2 the time, flicker off/on, come one when wires are wiggled, etc.). Wiring's tricky & need a tad more info...
Sounds like it has to be the device or the install of the device, is it possable you might have pinched or pulled a wire while installing the seat or side covers? Did the device work before you installed seat & covers?