Just a follow up on this one. The battery does drop down to 30 volts when under full load. I drove it for a bit, back and forth. Then started to turn the pump on and off alot while driving back and forth. Sure enough the code 49 goes off and shuts down. It did that a few times. So I checked the #5 scr connections and all was ok. I put a new #5 in and it did nothing to fix it. So then I thought is the pump contactor grounding or something like that. It has a external coil supressor (diode and 100 ohm resistor in series) connected on the terminals. Took it off and the resistor falls on the floor. It was broken. Checked the diode and soldered on a new resistor. The truck stopped doing the code 49 thing. Yeah.