Obviously if there is a problem with the truck I would rather fix it than retrofit a heater and a thermostat. The truck is a Linde B30TES with equipped with BTC2000 transistorized controls. We have 2 identical trucks and have taken the travel card out of each machine, put it in a freezer overnight, reinstalled it and neither truck will pick up the forward or reverse contactors. We have also disconnected the thermal switches at the drive motors and the contactors still won't pick up. The cards have been spayed with a sealer that also acts as an insulator that Linde recommends in cold storage applications.
The other odd thing is that when then truck quits you can push or tow it and the contactors will pick up and the truck will operate fine. I have been told the reason for this is that the drive motor(s) have become generator(s) and have sent a spike to the card.
I can see where there might be a problem if only one truck had a problem but it seems to be way too coincidental to have both trucks malfunction identically. If you have any suggestions, I'm all ears.

Can anyone tell me what the Crown part#'s for the thermostat and relay are? Is there a kit that I can buy? How is it hooked into the system? Any additional info would be appreciated.

Crown has a thermostat. It is best used with a relay. This heater gets really hot. Not sure what is will do if you tape it to your card. You can fry bacon on the heater.

Thanks Truck Tech. Can you describe what the heater strip looks like. Is it something that can be taped to the card's aluminum housing?
I think the biggest difference in my application is that I need the heater switch to be on when the truck is idled, not when it is use, so I would have to hook up a switch for it.

36V Heater Strip,Crown part# 088889,about $52.00 a piece