HVAC controls

[mrmudd]

Blower motor was working intermittently now it has stopped completely. Before it stopped you could not change from vents to defrost. Unable to turn on AC or mirror defroster. Changed out HVAC control assembly and still nothing. Its throwing a p1502 code. Sure could use some help on this. It's a 2003 dodge ram 2500 5.7l

 

[MosleyJu]

P1502 Meaning
Indicates the Powertrain Control Module (PCM) detected an error in the vehicle speed information. Vehicle speed data is received from either the Vehicle Speed Sensor (VSS), Transfer Case Speed Sensor (TCSS) or Anti-lock Brake System (ABS) control module. The P1502 code sets the same way as P0500.

 

[FabricGATOR]

Blower motor intermittent may likely be the resistor (fan speed controller) If after checked fuses and maybe if you see an HVAC blower relay and swap it out with something like horn or fog lights, then look towards the resistor.

In days of old, they would slow down the blower two or three steps by adding resistance into the circuit like an electric stove coil. This resistance would use up some of the power and make the blower run slower. Today it is done electronically but we still call it a resistor.

The inability to direct air to the defrost windscreen is a blower door actuator and I am understanding that they are a common weak link