AFT Controller query

[fortheloveofbaz]

Hello all - my first post on the forum.

My AFT no longer lifts. I have checked interlocking switches and all seems to be fine. When I try to raise the roof, the beeping sounds, dashboard lamps dim, but the roof does not move. I am assuming that there is current being drawn by the motors because the dashboard lamps dim. Before trying to lift the roof manually to remove the motors, I thought I'd check the AFT control unit.

I have measured the voltage across the four wires going into the larger plug on the RHS of the unit. I believe that the green wire is from the battery (when ignition is on) and black is 'ground'. Red and blue feed the motors. When I measured the voltage across the black and green I got 25V, which confused me as the battery is 12V. When the roof switch is activated to raise the roof, I then measured 16V across the black and blue and 0V between black and red. I was expecting the same voltage to the red and blue wires as I have assumed that red feeds one motor and blue the other motor.

Does anybody know what voltages I should reading across each terminal in the plug and/or another way to test the AFT unit?

Any help/advice greatly received. I want to rule out the AFT control unit before attempting to access the motors

[g8dhe]

It sounds like stalled motors, normally caused by corrosion products after a winter not used.
The circuits from which you can estimate voltages on other pins are all online but need a browser that uses Flash see here both for links and previews (low res.) on the page viewtopic.php?p=723219#p723219

[fortheloveofbaz]

It sounds like stalled motors, normally caused by corrosion products after a winter not used.
The circuits from which you can estimate voltages on other pins are all online but need a browser that uses Flash see here both for links and previews (low res.) on the page viewtopic.php?p=723219#p723219

Thanks for the link above. And as suspected it was a seized motor. Managed to get the roof lifted this weekend, motors out and test on the bench. Drivers side motor was seized solid, but I managed to strip it down, clean and reassemble. Reinstalled the motors and after a bit of jiggery-pokery with the roof, tested it tonight and the AFT is working again.

Happy days!

[g8dhe]

That's good to hear, that's the most common electrical fault with the roof. Trick is to keep it in use as often as possible especially during the winter months try to raise it at least once a month if not weekly!

[Bob]

Great result, well done.