We need to bear in mind that this only developed after you'd changed the battery.. Right ? Or had it been playing up with the old battery ? I think I'd pull all the relays and see which one cut the power to the unit, then do the same with the fuses. That would confirm what was what. The fuse is lower center and the relay should be lower left. You did see that last pdf I posted ? Then I'd try and find that diode it mentions. It should be right top or second down. If the battery had been connected backwards for an instance it could have blown the diode, and when the old battery was low voltage that can cause excess current draw which might have damaged the diode. I'd check the kill switch carefully. It may be a double pole switch and one pole/contact might not be working. Most of that though should have set a code. About the only thing not listed as a code is a worn or stuck brush in the PS motor, though it may be a stepper/brushless motor anyway.. The common cause in cars when there is no code set is either that it's a mechanical fault, or the power supply or earth is the problem and at the instant it's occurring the computer isn't powered and can't log a code ! So... I'd check the 14.4v didn't drop when it got a load on it. To put an electrical load on the EPS unit you have to put some force on the steering. I'd do that and see if the voltage dropped right down, which would mean there's a bad connection in the power or earth supply( you have checked all earths ?), or if it dropped slightly which would indicate the unit is trying to work but perhaps the motor's brushes are stuck or worn out, or if it didn't drop voltage at all in which case it would mean there was something wrong with the control unit or the EPS electronics. I'd check for voltage drop at the EPS control unit too when it had a load being applied to the EPS