Faulty Passenger Door Window Switch

[dahozzman]

Ok, I just went through a learning curve well worth sharing on this issue. Background, in searching through the forum, one of the common issues is the passenger window switch having faulty operation of the window. In my case, the passenger side switch would roll down the window, but had no effect to roll it back up. At the same time, the passenger window goes up and down no problem when operated by the drivers door switch. So, one would conclude I have a faulty drivers door switch. WRONG!! I did a search and found one post where the dealer advised a SC owner that the wiring indicated the drivers door switch was the culprit. He replaced his driver’s door, and stated everything worked fine then. Despite reading this, I remained skeptical that was the same conclusion in my case.

Thinking I had dirty contacts, I took the passenger door window switch apart. Anybody that might want to do this, know you will loose the LED light in the process. The switch comes apart by prying out (at the 4 tabs) the white body from the black case main body. However, the LED bulb is held by a main body while the two power leads are soldered into a circuit board part of the white body. Now way other than to continue to pry up on the white body until the two power leads simply pull out of the circuit board in the white body. Because of the design, there is no way to re-solder the leads back. Thus, why the bulb is lost. My justification was simply I was more interested in a passenger being able to operate the window than maintaining the little green light. Anyway, since I've confirmed the problem isn't the passenger switch, I only memorialize this information for future users of the search engine.

What puzzled me is that the passenger switch would work intermittently. So, after putting everything back together I discovered that if I press straight down (NOT ROCK IT) on the drivers door switch that operates the passenger window, I found that I could roll up the passenger window with the passenger door switch. Said differently, while holding up the passenger door switch, the window would only go up by at the same time pressing down on the drivers door passenger window switch. Clearly, the center portion of the rocker contacts within the drivers door switch had developed faulty contact. That the wiring design is such that the "up" power from the passenger door switch flows through the drivers door switch and only then back to the window motor. Very weird design, but that’s what we've got in our SC300's and SC400's.

At this point, I took out the driver door switch module. It is held in the bezel by three silver screws. The cover to the circuit board can be removed by !Removed! out 4 brass colored screws. It is at this point I found that even when removing the brass screws, the circuit board would not pull out. The same LED casing design probably holds it in place. So, I stopped there.

Bottom line, if your passenger door switch starts to show faulty operation, do the press down test on the drivers door switch before you do anything further. The drivers door switch is far more expensive to replace than the passenger door switch. But by my experience today, more than likely the drivers door switch is the one that needs replacing. :(