As far as your InfoLink card readers failing... I think that is an issue Crown has with the card readers themselves. My company just jumped on board with InfoLink about 6 months ago. The dealership came in and installed Infolink on all 70 of our trucks. In the last 6 months I think we have had at least 12 card readers fail. Talking to the local road guys it sounds like they replace quit a few of them.

Redman,
your voltage thing with the motors is not specific to crowns design, all motors can do it, especially if they have brushes. Even brushless A/C motors can do it if they get enough dirt in the field windings.

As for your Motorola radios picking up voltage through the mount?
I'd say the radio was intended to be grounded through the mount so you could isolate that by going into the radio and moving the ground from the mount to a separate ground that would connect directly to negative, of just removing it all together, it's probably a secondary ground point. But your solution of isolating the mount plate is probably the simplest solution.

We installed Motorola two way radios on all our lifts. While disconnecting components we found some lifts dropped to 14 volts when the radio was disconnected. Others remained at 26 volts. We had to isolate the radios by installing a insulator between the radio and the Crown accessory clamp.

What do you mean by the radios you installed?

Just an update on my voltage to frame issue. After disconnecting component after component I have found a issue with the lift pump. The voltage to frame was 26V,after I disassembled and blew out the motor my voltage dropped to less than 2 volts. I feel this is a design issue with Crown. There is no access to blow out the motor. Let my say again, the lift is working fine. No error codes. We are having issues with INFOLINK card readers going bad. Can anyone tell me if voltage to the frame has an effect on these readers. So far I have disassembled and cleaned the lift pump on four lifts and three dropped to less than 2 volts and one was less than 1 volt.

I considered rigging up a light bulb and toughting it to the frame. I don't think we have a 26v bulb in the shop. Is there another way to test a short to frame?

Have you ran a short to frame test?

I did that, voltage stayed the same. We have Hydrogen fuel cells. All lifts are less than six months old.

try pulling the battery, get a jumper extension harness for the battery, connect it to the truck while the battery is out of the machine and then see what you get.
In most electric's i've worked on, especially older units with older batteries the batteries tend to get acid between the cell's and can cause a bleed effect from the case of the battery to the frame and it back feeds through the motors into the electrical system. If your motors are isolated well from the frame then check the standoff isolators on the power cables, there are some in the main battery cable circuit to the panel, i have seen those go bad on occasion.
Most of the time you may not even notice anything wrong (except if you have accessories attached, they do not have the capability to handle any huge differences caused by this which may be why your having issues).
Once you get the battery removed, if the voltage dissappears theres your answer. If it does not then go by what crown said and start disconnecting components till it goes away.