Is this broken or not?

[t_marat]

Attached are pics of the A/C control panel. I bought them from Ebay. The buttons to the far right, which switch on the air conitioner, rear window heating and closed loop ventilation are different from the ones that are in my car.
Mine have lights behind the buttons which light up when they are activated. On this panel, if you press buttons they keep depressed (on), when you press again, they come out (off), as visible from the pics.

But the button which controls the rear window heater does not have any fixation, after you press and release it, it comes out, it does not keep depressed. Well, is this a broken button or is it supposed to be like that?

[Jesda]

As far as I know, the rear window/heated mirror button is timed so there's no fixed position for it.

[t_marat]

Well, that also came to my mind but the unit in my car lets you switch it on and off at any time. So I thought maybe it is broken.

[Jesda]

Well, that also came to my mind but the unit in my car lets you switch it on and off at any time. So I thought maybe it is broken.

You can switch it on and off anytime, but if you leave it on, a timer will eventually turn it off.

[t_marat]

yeah, I know, it eventually switches off. But with the unit pictured above, is there a way to manually switch it on and off?

[Jesda]

You push the button again to switch it off manually.

[t_marat]

You have this type of controls in your car? I mean there is no way to know for sure unless you tried it yourself while its fitted in. there are no indication lights.

I am planning to resell this thing so need to know for sure that it works fully.

[wingman]

Mine has the lit buttons and there is no fixed position. As you say, with this one how do you know when it's on or off!?!? It sounds like it works alright but must be from a car that has a light elsewhere to show status.

[Anthony (M5 in Calgary)]

Your pictures show an early type switch panel. The entire button lights up when active. Later cars ~'91 and up (and likely yours since you say it's a '94) use momentary buttons in all 3 places and have small lighted areas instead of illuminating the whole button.

I don't think the switches are interchangeable since the later cars must use a latch type circuit in the heater control module to mimic a latched button. I know the early circuit will only work if the AC or re-circ buttons stay down since I had a broken switch on my '90 535.

In any case, pressing the defrost button starts a timed cycle. After a while it switches to a low power mode and stays on low until you cancel it and start the timer again by presssing the switch twice.

[Jay 535i]

It's supposed to be like that, so when the rear defogger times itself out it doesn't leave the button in the "wrong" position. There is only one position for that button.