1999 328 i convertible - United Bimmer Community

**Mcat** · 01-17-2010, 12:46 PM

hello all: Need advice: the driver side window does not work, all the others do. would anybody know if there is a relay and where is it located that I could check? The fuse that controls both driver side and passenger side windows is OK. When I push the window switch I can hear a small click in the area of the glove box compartment. The Haynes manual 1999-2005 refers to "majority of fuses and relays" being located behind the passenger side glove box, but that does not seem to match what I see in my car, maybe it does not apply to convertibles?

**k3nd0** · 02-05-2010, 10:52 AM

BMW did not make an e46 convertible in 1999. Do you have an e36 convertible? The e36 is a little more boxy looking than the e46. I suspect you have the wrong manual, which would explain why your car doesn't match the instructions.

**Mcat** · 02-05-2010, 11:11 AM

maybe so, I don't know the difference between E36 and E46, but I know mine is a 1999 model. I called the mechanic, he said here is no special relay for the windows, said it was either a bad switch or the motor, I took all the door apart, exposed the motor and regulator but they seem to be screwed from inside the door cavity - the metal plates that form the door and are apparently welded together or made of one metal piece. so the heads of the screws holding the regulator and motor apparently cannot be reached. do you have any experience with this? thanks.

**k3nd0** · 02-05-2010, 12:27 PM

Is this vehicle equipped with an alpine car alarm? Does either the window switch on the door or the central window switch operate the window? Do neither switches work?

**Mcat** · 02-05-2010, 02:15 PM

thanks for your comment regarding the manual not being the right year, thta could be, I will look into that. on this car there are no switches in the doors, but there are two switches on the central console that can operate this window: one exclusively for the front left window, one for all windows at the same time; neither one can lower the front left window, but the second one operates the other 3 windows ok. to me it looks like the motor, just have to find a way to take it out so I can make sure that is the reason and replace it.

**k3nd0** · 02-05-2010, 05:02 PM

Thanks for the info. You're right in that, assuming a single point failure, the issue seems to be on the output side of the circuit. However, that doesn't necessarily mean that it's a bad motor.

Personally, I like to know for certain what is broken before i throw parts at it. For example, anytime you have a circuit going from the instrument panel to the door the wires in that rubber boot that connects the door to the cab is suspect. If you have access to a test light and a digital voltage and ohmeter (DVOM) I can walk you through the process of identifying the problem. Or you can just throw a motor on there and see what happens. I'd say you have a 70% chance that the motor fixes it.

**karimMsalama** · 02-07-2010, 10:07 AM

thats a good car

**k3nd0** · 02-07-2010, 11:20 AM

Regarding removal of the window motor, it's not that you can't find the screws. There are no screws. The window motor/regulator module is riveted onto the door panel. To remove it you must grind off the rivets. When installing the new module, the rivet holes must be bored out and over sized nuts and bolts used to secure the module. Yet another good reason to be sure that it's the motor before replacing it.

Even though your car is a 1999 model, it is the old body style (e36). The manual that you need is the 1992-1998 3 series repair manual. I suggest buying a Bentley manual instead of Haynes, but they cost more.

**Mcat** · 02-07-2010, 01:15 PM

thanks, great advice. obviously this thing is not meant to be repaired by people like me. Anyway I took some snapshots if you care to look at it

http://www.flickr.com/photos/47324377@N03/?saved=1

thre are two electric connections going in: the upper one has two wires, the lower one three thinner wires going in. I assume the upper one is the 12 V power so I measured the voltage when pushing the window switch: it goes up from 0 to about 5-7 Volts then goes back to zero within a fraction of a second while still pushing on the switch. same thing with the other switch that controls all windows at the same time. Does it mean anything? should it not geat a steady 12 V power to move the window??

thanks a lot for your time

**k3nd0** · 02-07-2010, 02:07 PM

Did you get the same voltage on both of the wires? One should be purple/white and the other black/white. The power window motor circuit is controlled by the Body Electronic Control Module, and will shut off after .3 seconds of inactivity. This is why you're seeing the jump in voltage and then nothing. Also, you're not going to get an entirely accurate reading because of this. 5-7 volts sounds like a good reading, assuming it's the same on both the purple and black wires. The reason that i say it sounds good is that 5-7 is about halfway between B+ voltage and 0. The circuit is closing and opening too quickly for the voltage meter to get a good reading, so it shows an average. Some voltmeters have the ability to capture the highest voltage over a period of time and display that instead of an average. If yours has this feature I would try reading it that way and see what you get.

When I say that you should have the same voltage on both wires I mean that one should have B+ voltage when pressing the switch up and the other B+ voltage when pressing the switch down.

**Mcat** · 03-16-2010, 01:37 PM

thanks a lot. I did buy the 1998 Bentley manual, much better than Haynes despite the price. do I understand correctly that the glass needs to be removed in order to get the regulator assembly out so that the motor can be tested? The Bentley manual talks about the need to raise and lower the window during removing the glass, and that is something that I cannot do since the window is stuck in the fully closed position. even if I could move the glass up and down the procedure as described in Bentley seems difficult .... maybe time to give up?

**k3nd0** · 03-16-2010, 08:36 PM

You see that crescent shaped lever with all the teeth on it? That is what the motor acts on to raise/lower the window. You might try to either pop it off the motor or use one hand to push the window down while pushing up on the lever to lower the window. If you can get the window half down you can disconnect the regulator and pull the window all the way up and jam some wooden shims in there to hold it in place. You do not need to remove the glass on a convertible.

Let's talk about the 3 wire connector for a second. We know that we have voltage to the motor when the switch is activated, the next thing would be to figure out why the BECM is cutting the power right away. Those 3 wires are for a potentiometer, which is how the BECM knows what position the window is in. Basically, a potentiometer is a resistor with a reference voltage (usually 5v), a ground, and a signal. The BECM sends the reference voltage through the resistor and out the ground. The signal gets a varying voltage depending on where the window is. It's possible that if there is an open in the ground or signal the BECM might think the window is already in it's lowest position and cuts power to the motor. I can't tell from my schematic which one is the 5v reference and which is the signal, but it's one of the black wires. The brown wire is your ground. So with the key ON try to get a voltage reading on the black wires, you should get 5-9v on one of them (I'm not sure what the specs are). If you're getting voltage the next step is to make sure we have a ground, so we want to Ohm the brown wire. It should be nominal resistance, like .25 Ohms. The other black wire is a little tricky because I don't know where it goes inside the BECM, but if the key is on and it reads OL or ridiculously high it's a problem.

Something else that I came across looking at BMW DIS was a document talking about how the driver door can get stuck if you disconnect the battery. When did this problem start? There's something to do with the convertible top that allows the window to get voltage through a circuit breaker (I think it was labeled F56 but I couldn't locate it) before the BECM comes online. Anyway, the fix was to trip circuit breaker F56 (I think). If you can locate the circuit breaker in your Bentley manual it might be a quick fix.