2003 Dodge Ram, remote start

Installed a remote start in a 2003 Dodge Ram a month ago and owner called and said it will start and run for a couple minutes then shutdown.There is no factory security system installed.It has worked fine until now.It is a Design Tech model 23927.Anyone know what the problem might be? I called tech support and they told me to hook it up for tach,but it has worked fine without tach til now.Anyone know what it could be? Thanks!

Unless the unit has a programming option to adjust the voltage-sensing threshold, connect tach. I would take a guess that it worked fine before because the air conditioning was off......... now it is hot out........if the AC is switched on, the voltage doesn't rise enough to satisfy the remote starter.