Lowery Promenade organ LX400.

go to Google or YouTube and in the search box type in your Lowery Model # and search for "Manual for Lowery Festival with Magic Genie Organ

full volume ??? hum that's funny , as if pedal has broken one would suspect that it would go to lowest volume and stay there , 1st id ck to make sure the "bright" switch is not on or stuck on then id dive into taking the cover off the pedal assembly , for a look around to see if somethings obviously not right in there (hanging springs, swinging levers, etc)

There may be few things that would cause that. I would suggest having a repairman local to you check it out.

To find a repair person, contact the largest organ dealer close to you for a referral, or search this site-

Find Service Center MITA International

If you turn off any voice tabs for the pedals, they are effectivly turned off.

You can get a manual here:
Lowery Organ Manuals Mx 1 Downloads

Lowery Organ Manuals Mx 1 Downloads

We can only guess at what model/brand you have.

OFTEN such low volume things can be traced to a burned out light used in some expression pedals that use light dependent resistors to vary the volume.

Be aware that on some organs things like rhythm drums MAY go through a different set of speakers and amps than the other voices.

Probably needs the filter capacitors in the power supply replaced.

The electrolytic caps dry out after years and become ineffective in filtering to get pure DC current for the electronics.

Other less likely possibility is a broken ground wire someplace within.

For a damaged cord, just buy a cord wot correct plugs on it and open pedal and replace the cord. There are usually only two wires to worry about.

IF the expression pedal uses a lamp and light-dependent-resistor, check for burned out lamp at the pedal.