# Truck trailer locks



## mpcxl (Dec 9, 2015)

This is an old manufacturing facility with tractor trailer bays for shipping and receiving 

The old controllers for trailer locks all have their key switches ripped out for some odd reason

If the lock is engaged and no trailer is present, the controller will go into alarm and will not release when release button is pressed

The only way to retract lock is to manually push broken key switch

Is anyone familiar with these controllers and why is it operating this way?

Why won’t the lock retract when the release button is pressed?


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## mpcxl (Dec 9, 2015)

Pics


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## gpop (May 14, 2018)

They don't look that old which means there probably a manual online. 

Its no surprise when a safety is energized it latches until the do something to unlatch it.

Its also no surprise that the reset is a supervisors key. They tend not to like things that move that they can not be seen from the control panel. Normally a trailer is in the way so its safe to move the arm but as the lock detected there was no trailer its in alarm.


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## joebanana (Dec 21, 2010)

Is that a schematic in the lower right of the panel?


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## bostonPedro (Nov 14, 2017)

One of your pictures has paperwork. Is the schematic in there? 

Wired up controls to a pump for waster water recently that had no paperwork because someone opened the box and it more than likely got thrown away by the laborers...luckily I knew there were 2 other pumps in another area that were wired up and had the paperwork in them.


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