Just a fallow up, Ended up scraping the unit was in pretty rough shape. Ended up using the complete board system on another unit that was sitting out in the rain for 4 months so wasn't a electronic issue. sent motors to be remand haven't received them back but my guess is the right motor was a 48 volt. Thanks for all the input.

You may be on to something. I have had the plastic come off the plate and had one do some weird things and never coded out.One motor could be fighting the other. I'll have to check that out. When i figure it out I'll post my findings.

yeah that sounds pretty rare to have all 3 be defective at the same time, but i suppose it's possible ;o)

ok, well if you have the diode board covered and it is ok, then my only other educated guess would be the steering wheel angle sensor, but that's a long-shot being it 'should' only affect one side or the other and not both at the same time if it were out of center. (theoretically anyway) :o)

Yes i have done that i keep 2 of them in stock that is a big problem with them along with the igbt and diode taking out the board. Try to keep most of the electronics in stock. The company i work for makes pickles so you can imagine the environment there in wet, salt water, vinegar,ect.. but i did run into a problem a few years back where everything pointed to the h bridge board and eventually figured out i had 3 defective boards in a row. Thanks

have you removed the logic card and power dist board and looked at the diode 'drive' board?
these trucks were notorious for buring up those diode drive boards if they were ran on low battery power for too long a period. That can cause all sorts of strange drive system problems from running slow to not running at all.
You might want to take a look at that board and see if any of the diodes on it are burned. They are 1/4 watt diodes so they are fairly large and easy to tell if they are damaged from heat.

Yes i have ran into that before. Had to get info off unit was at another plant i take care of 36 lift trucks and 22 electric pallet jacks sometimes it's hard to keep them all straight. ser#etb5b5108. Most of our trucks are cat ep16kt or et3000 models. The wires on that one are yellow and green for heat sensors and purple and orange for brush sensor. All that seems to be operating fine wires test fine and display is showing brush light when they are jumped and heat light when i disconnect heat wires. The unit will get up to 6 mph on straight away don't want to go up a grade or turn do to lack of power. Have power setting set to high speed set to top speed and accelerator on fast. Thanks

what addams says is correct, sometimes these sensor wires at the motors can be damaged from debris getting thrown up inside that comapartment and if they do disconnect for any reason it will slow down or even disable the truck drive.
but having a serial number will still be needed to make sure you get the wires connected correctly, there are color codes on each wire and they did change at some point in the newer models to some different colors.
If the dataplate is missing just look along side of the battery compartment on the frame and the serial number should be stamped in the frame there. Most of the cat trucks did have 2 dataplates though, one on the hood and the other located on the front frame between the mast and truck frame.

EP16KT chopper model don't know serial off hand. Checked heat wires and brush wires on motors cross brush wires light comes on disconnect heat wires light comes on so sensors and wiring up to par. Started doing it after i replaced motors. we run 48 and 36 volt. Thinking that when we had rebuilt possibly rebuild company tagged wrong voltage. When jacked up left motor seems to turn fast and left slow. Need ohm reading to confirm not in cat manual. do you know difference from 36 to 48 volt for field ohms?

You might check the wire connections to the drive motors. such as brush indicator and thermal cut out Raise mast up and chain it for safety you will find that connection cluster there. if wires break or come unpluged truck will only creep. something to check

need a full model and serial number