Stan.Shaw@Excell.Net

Think of buying windows switches for 90 GT and see they are different from 90-95 as well as more expensive.

Does anyone know what the difference is from the older switches?

Jim bailey - 928 International

They only have three wires instead of 4, ! completely different switching circuit ...

Stan.Shaw@Excell.Net

Thank you Jim. Mine work, but not well, so I will clean them, bend them, etc. first then order them if I need them.

Jim bailey - 928 International

The later windows have the control unit 928 618 040 00 which gets signals from the switches same unit helps with the automatic closure of the sunroof and windows when you lock the doors arm the alarm ...

Stan.Shaw@Excell.Net

Thanks again. Not sure those features work, guess I will have to review the manual. It appears the driver's door lock was replaced at some point as the key to that door is unique, and it may be causing some alarm issues like the headlights blinking... Looks like I will be learning quite a bit about this system at some point

shawnzo

Jim, does that control unit engage after the switch is pushed? My drivers side window stopped working, but I can hear a clicking as if the switch works, but some sort of relay does not. Thanks, Shawn

Alan

On the later window modules all the driving of the motors is by relays in the window controller (under the drivers seat) - the switches are low current only. With engine off - especially if the window motor isn't running - you can hear the relays click.

Incidentally in one direction 2 relays change - in the other only one - so a click may not mean all things 'relay' are working correctly. The relays are unencapsulated inside the module and are permanently soldered down - not easily replaced...

If your window stopped working - its still much more likely its a motor issue - the motor lives in quite adverse conditions - unlike the rest.

Alan

docmirror

Also, these relays can be a latched style so the drivers window goes all the way down with one touch of the button. If you have trouble with the windows, or sunroof working right, try various combinations before tearing things apart. sometimes only one circuit can be active at a time.

Try this: Engine running, operate the sunroof all the way back, then release the button. Now go forward, but not all the way. Now try one of the windows. If they don't work, the window relays are locked out by the operation of the sunroof, even though it's not moving. Now move the sunroof all the way forward, and try the windows, one at a time, either up or down.

Fiddle with it for a while and you may see a trend where one relay is sticking on, and inhibiting another relay from working. BTW, I can rebuild your switches to like new operating condition. This may or may not resolve your window issue, but I've been doing Lamborghini, Ferrari, Maserati and Porsche switches for a few years with good success.

Alan

On the later modules the electrical connections of the switches seem to be good with little contact damage (due to the much lower current). The switch plates still warp and hang up on the console in all the same ways though...

Again check the motor first - probably 70%-80% of the later window system problems are there - and often easily fixed

BTW Doc - it doesn't work quite that way. It senses the motor stall current spikes to detemine when to stop driving - absent those it times out after the max open/close run time anyway...

If the module stays unresponsive for >10 seconds after the last button keypress - there is a bigger problem...

Alan

docmirror

The relays are latched until something, in this case motor stall current tells them to unlatch. Try the experiment and see what happens. I haven't timed it for the 10 sec, but I can assure you the drivers side will lock out other operation temporarily. It does it on my car with regularity.

Alan

OK I see what you mean - I thought you were saying they are latching type relays...

The processor controller continues to drive the regular coil relays until it senses the motor current spike. If the motor stall current isn't sensed for some reason - different motors, motor problems, controller out of calibration (whatever) - then it takes longer (till its timeout) before it will sequence on to the next window.

Agreed then you can also hear it click off well after the motor stalled. I'm not sure that the timeout is exactly 10 seconds - but its something like that.

It does seem like a very long time if the window was already mostly closed and you still have to wait and wait...

Alan

69gaugeman

I got that joke

Alan

Sorry Rod - sore point...

Alan

Earl Gillstrom

Alan,

Interesting observation. "The processor controller continues to drive the regular coil relays until it senses the motor current spike." It seems to work on the windows, but not on the sunroof. Every sunroof that I have tried opening seems to drive the motor for a predetermined time after the sunroof is fully open with the clutch slipping for a few seconds.

Another observation: I did the "auto up" disconnect the jumper on my car ('91GT) and love it. But, sometimes when I open the drivers door, the pass. window goes down a few inches by itself??? My controller is pretty new since the old one kept eating its relays.

Alan

Earl, interesting passenger window behaviour there... I assume that means its initially thinking the button was pressed when it powers up...

Its probably a fault in the unit - I assume it has pull up resistors plus possibly a capacitor on the switch inputs which normally just float high. The active switch positions is to pull these low. If it really bothered you it could probably be band-aided to eliminate this.

My sunroof doesn't operate this way. Best way to test this is to use the memory sequencing - with ignition on open the sunroof most of the way - stop before its fully open. Then press sunroof open & a window open one after the other and see if the controller transitions to opening the window as soon as the sunroof is fully open or if it waits before doing this.

I have heard of this issue before on windows too - often just one side... I think if the mechanisms have too much friction its harder for it detect the current spike. I don't know if the detection is adaptive or at a fixed level here... seems like its adaptive if it does this - if so I'd assume it would adapt everytime the battery was disconnected...? just a guess.

Alan