DISA mystery.

Oldmactech · #1 08-15-2022, 12:15 PM

My Scanner shows DISA inactive at idle and revved a bit. Pulled it off and the flap is good and holds a vaccum. Connecting power to it nothing happens (no motor movement) but oddly the connector tests 12v with the key in, ignition on and 13+v at idle.

Pretty certain 12v is too much but maybe not since it has to move the vacuum arm.

Tried an aftermarket DISA, still no movement.

Not finding and electrical diagram in Bentley for DIsA.

Help please?

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Clavurion · #2 08-15-2022, 01:06 PM

https://bmwteka.com/wds/en/e53/f68ff08d

Oldmactech · #3 08-15-2022, 02:01 PM

Thanks.
So 1/2 a volt is correct. Wonder why I’m getting 12v?

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Clavurion · #4 08-15-2022, 02:32 PM

Quote:

Originally Posted by Oldmactech

Thanks.
So 1/2 a volt is correct. Wonder why I’m getting 12v?

Where did you figure that 1/2 a volt? The positive side has battery voltage from E-box fuse (these are activated when DME relay is activated on ignition pos. 2) and a swithed ground from DME. When DME activates that ground solenoid opens a route for vacuum bell to pull the rod. If there is no vacuum obviously it won't work.

Oldmactech · #5 08-15-2022, 03:36 PM

Looking at the wiring diagram, between the DISA and the DME seems to .5? Is that not 1/2 v? Clearly I’m not skilled at reading these diagrams.

I did pull a vacuum at the tiny hole near the flap and with the DISA out reconnected it and turned the key to on. I hear a buzz but nothing moved (as it does on Youtubes I’ve seen).

I also tried with a replacement DISA that I had-good vacuum, no movement.

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