Weirdest problem I’ve ever seen - IDX MX8

[HighOctane]

I’ve been having an issue with three of my bays on the west side of my pump room. When any of the low pressure options (presoak, tire engine, bug remover) are selected, the air will work but no soap will come out.

Here’s where it gets weird: let’s say bay 3 is set to presoak. This presoak will only blow air and not soap. If any other bay dial is set to presoak, bay 3 presoak will start working. The selector switch only has to pass by momentarily and the presoak will start and stay working. This can be seen when looking at the IDX MX8 controllers. The LED indicating which bay is active will come on but the output LED will remain off - once another bay (even one of the three that aren’t working) selects the same option the output light will come on and stay on. I’ve attached a video that shows this. The service tech guys are stumped.

I have swapped faceplates with the three bays that are working to isolate the problem - it’s somewhere between the three bad bays and my pump room. Faceplates / rotary dials are not the problem. I’ve swapped the Dema solenoids on my low pressure options and installed new Dixmor timers.

Has anyone experienced something like this before?
Video link:

https://imgur.com/a/xBgYuv7

 

[Randy]

It looks to me like you have a bad MX-8. Get out the voltmeter and check to see if you have power coming out of the MX-8.

 

[TMoliver]

You said it was happening to the 3 bays west side of the equipment room. What about the east side of the equipment room? Looking at the pictures I see 2 unused terminals. Try moving lets say bay 3 wire to #8 and see if the issue moves or correct's. Or swop 3 and bay 4 as well. If issue moves it is the MX8 if not it probably a loose common connection on the west side .