Florida Pumper

When pumps are ingaged rpm comes up to around 1050. That’s why oil pressure is up.

Oil pressure will read around 40psi. Temp level ok and at 185

1999 mr.  warning buzzer go’s off then truck dies.  Will start right back up.  Usually happens when I’m out ok cab as it is a concrete pump and operated remotely. Did have buzzy go off on way hame Friday and raised rpm’s up and it went off. Tried to hold set button for cruise to get code but didn’t give one.  Only happens at low rpm’s long as I don’t idea it down to far runs all day. Also hooked cheap scanner up and didn’t show any codes.  May not give a code while pumps are engaged because control panel for pumps utilizes cruise control circuit for throttle.  

A/C -HEATER ISSUE IF I  WASNT CLEAR.

Lost power to fan switch and compressor. 2005 Mack mr688. Can’t find a blown fuse-there are a bunch of relays tried swapping relays around didn’t solve.  Don’t have diagram on pane cover.