Sealco 110500 slow to set spring brakes

Wait actually that would be incorrect. I think it just prevents brake compounding.

 

So that service signal goes back to a ABS module/computer and that is where all the service lines come from. That abs module isn't that old either. The only other place that blue service line goes is towards the front. Any idea where my issue could be?

 

I aired the trailer back up and then released the brakes. NO AIR at the blue service signal line. Air is still draining back out the red gladhand until the trailer tank is empty.

 

Here is the 110500. It is brand new I just picked it up yesterday. The one before had the exact same issue. I turned it in for a core. I also have an old one I kept.

 

Here is the abs computer/service brake controller. That blue line goes to the 110500 service signal port.

 

None of the brake canisters have any audible leaks. That service controller isn't all that old. I definitely don't want to buy a new one because it is EXPENSIVE. Plus the service brakes work properly. The trailer literally just has this one issue and it is kinda driving me nuts. I suppose at that particular warehouse I could just manually drain the tank quick before I drop the trailer off. It would then pass the "tug" test even if they picked it up immediately.