530t with resistor mod still wont work

Hi All,

I have an older car (1991 BMW E30 Cabrio) with very high load window motors. I wired in a 530T (stock), and tried all of the resistance settings. At the highest resistance setting, the front window rolls all the way up, but only goes about an inch at a time on the way down before the 530T relay clicks. The rear window won't move at all (instant relay click).

I did the resistor mod to increase the 530T resistance handling, and the result is unchanged. The windows work fine with the stock switches, but they are indeed very slow. Motors are probably very inefficient, tracks might need lube, etc.

Wiring to the 530 is done with 10ga straight to the battery and properly grounded. No difference with the car on or off. Stock wires from the switches to the window motors seem thick enough (at least 12 or 14ga).

Has anyone looked into further modifications to the 530T for very inefficient motors? More to the point, does anyone know exactly how the 530T senses the load? I'm comfortable soldering/rewiring the board (work at an electronics company with all of the appropriate tools and supplies). I'm wary about just replacing the new 150ohm resistor with something much larger without having any understanding of the circuit...

Thanks in advance!

--Ckk

Thanks all,

metz35: I have a new version, it's the one with the 150ohm resistors already in place. Based on the directions, I removed the r32 and r40 surface mount resistors (looking at the circuit board I can see that those were just used as bypasses of the 150ohm parts. Dunno if there is an additional mod -- perhaps replacing the 150ohm resistors with 200 ohm or something.

I suppose I will have to lube the tracks. Not sure how to do that, actually -- is there a specific grease to use?

My fear is that the rear window moves perfectly fine with the stock button, smooth but slow, but with the 530 it doesn't move at all. Even if I lube the window track, I don't think it's going to go from 0 movement to 100%... If I have time this weekend I can take out the rear panels and see if I even have access to the rear window motor.

Thanks,

https://www.the12volt.com/installbay/downloads.asp?srch=all&term=1900

Thanks guys,

As mentioned, I already did the resistor mod to the 530T and didn't see any difference in behavior.

Howie, I am assuming that the problem is old gunked up motors and non-lubed tracks (I have read that a good cleaning of the motor internals can help), but they definitely work fine with the stock motors and buttons even without a cleaning. It's only going to get worse when I put the top up and they have to slide into a relatively tight slot in the top.

I wonder if I can use the 530T output just to drive a relay rather than to drive the actual window. The key question there, even if it works, would be how to stop it since it would be unable to sense the load.

Perhaps there are other "timer-based" window modules that I can use if the 530 doesn't work?

Thanks,

--Carey