B1004 — Blower Motor Circuit Open
What it means: Blower Motor Circuit Open.
How serious / can you keep driving: Serious. Power derate likely — plan to stop soon.
Check first: Check HVAC fuse
Don't risk it — look up listed providers near you and give them this code when you call.
Listed providers nearest Louisville, KY
Closest first. Tell them B1004 and what the truck is doing. RoadService.app lists these providers and does not employ them or carry out the repair.
- 0.0 mi away — based in Louisville, KY · (502) 773-1159
- 0.0 mi away — based in Louisville, KY · (502) 447-1234
- 0.0 mi away — based in Louisville, KY · (502) 648-6725
Seen on: Heavy Truck
What B1004 means
Blower Motor Circuit Open. Common causes: Blower motor circuit open.
How serious is it?
Serious. Power derate likely — plan to stop soon.
Most likely causes
- Blower motor circuit open
- Failed blower motor
- broken wiring
- blown fuse
First moves (roadside)
- Check HVAC fuse
- test blower motor resistance
- check motor power and ground
FAQ
Blower Motor Circuit Open. Common causes: Blower motor circuit open.
Serious — Power derate likely — plan to stop soon.
The most common cause is: Blower motor circuit open. Other possibilities include Failed blower motor; broken wiring; blown fuse.
Power derate likely — plan to stop soon. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Related codes
Codes that commonly appear alongside B1004, or share the same subsystem.
- Blower Motor Circuit Short to Ground (B1005)
- APU HVAC Communication Fault (B1050)
- Coolant/Diesel Heater Circuit Fault (B1052)
- HVAC Control Module Voltage High (B1001)
- HVAC Control Module Voltage Low (B1002)
- A/C Pressure Sensor Circuit Fault (B1010)
- Air Distribution Actuator Fault (B1040)
- Temperature Blend Door Actuator Fault (B1041)
Find a mechanic or related guides
General diagnostic guidance for diesel engines (Cummins, Detroit, PACCAR, Volvo, Mack and more). Not a substitute for a scan-tool diagnosis on your specific truck.