What this code means
B1241 may indicate that the HVAC climate control unit is seeing blower fan feedback that does not match the commanded blower target.
What the vehicle may do
- The blower may not run.
- Airflow may be weak or intermittent.
- Blower speed may not respond correctly to commands.
- Heating or air conditioning performance may feel reduced because airflow can be affected.
Possible fault areas
- Possible blower motor power feed or ignition feed issue.
- Possible ground or relay output circuit issue.
- Possible blower motor control circuit issue around BLW-M, BLW-V, or BLW-G.
- Possible power transistor, blower motor, or climate control unit involvement.
Diagnostic path
Opening and code meaning
On this 2017 through 2025 Honda CR-V with the 1.5 turbo engine, B1241 is a blower motor circuit fault in the HVAC system. In plain terms, the climate control unit is watching blower fan feedback against the target blower fan voltage, and if that feedback is not where it should be, it can store this code. The driver may notice no blower operation, weak or inconsistent airflow, or blower speed that does not respond correctly. Possible fault areas can include the blower power feed, ignition feed, ground, relay output, blower motor control wiring, the power transistor area, the blower motor, or the climate control unit. Before testing, make sure you’re clear on the overall HVAC troubleshooting approach. Then turn the vehicle to ON mode and run the self-diagnostic function with the HDS or with the climate control unit.
Main power, ground, and relay output checks
The first hands-on check is the +B_HTR_MTR, IG2_OPTION, ground, and BLOWER_MTR relay output circuit inspection. Disconnect the blower motor relay, then disconnect the blower motor 2P connector. Use the disconnected blower motor relay socket 4P female terminals and the disconnected blower motor connector 2P female terminals for the checks. With IG Mode OFF, the +B_HTR_MTR circuit should show 12 V battery voltage. With IG Mode ON, the IG2_OPTION circuit should show 12 V battery voltage. With IG Mode OFF, the ground open-wire check should be less than 1 Ω, and the BLOWER_MTR [BLW-RLY(OUT)] open-wire check should also be less than 1 Ω. If this inspection is abnormal, the fault is in that circuit. If the power supply part of this check is abnormal, continue into the power supply inspection path to locate the failure instead of jumping ahead.
BLW-M circuit check
Next, move to the BLW-M circuit. Disconnect the blower motor 2P connector and the power transistor 4P connector. Using those disconnected female terminals, check the BLW-M open-wire condition. With IG Mode OFF, normal is less than 1 Ω. Then inspect the BLW-M circuit for a short to ground. With IG Mode OFF, normal is more than 1 MΩ. If the BLW-M inspection is abnormal, stay in that circuit and find the circuit problem before moving on.
Ground, BLW-V, and BLW-G checks
After that, check the ground, BLW-V, and BLW-G circuits between the power transistor and the climate control unit. Disconnect the power transistor 4P connector and climate control unit connector B, the 24P connector. With IG Mode OFF, the ground open-wire check should be less than 1 Ω, the BLW-V open-wire check should be less than 1 Ω, and the BLW-G open-wire check should be less than 1 Ω. Then check BLW-V and BLW-G for shorts to ground. With IG Mode OFF, each should be more than 1 MΩ. If this group of checks is abnormal, the problem is in the circuit.
Blower motor functional check
For the blower motor functional check, the important precondition is that the external circuit is normal. There is also a useful note here: this functional check can be done before the other inspections because it includes the listed inspection items, but if it fails, the individual inspection items still have to be checked to determine what failed. For this path, disconnect the power transistor 4P connector. Connect power transistor connector terminal No. 1 to body ground with a jumper wire. Then turn the vehicle to ON mode. The blower motor should run. If it does not, the problem is with the blower motor.
Climate control unit decision and close
If the other inspection items all show normal, the remaining fault is the climate control unit. Do not make that call until the power feeds, grounds, relay output, BLW-M, BLW-V, BLW-G, and blower motor functional check have all been handled in order. Keep verification separate from testing: after the fault path is corrected, rerun the basic confirmation and self-diagnostic checks and confirm B1241 stays gone. The takeaway is simple: prove the circuit first, prove the motor function second, and only then make the final control-unit decision. For more diagnostic training, visit stepdiagnostics.com.
Final check
This code is often best approached as an electrical circuit diagnosis: verify feeds, grounds, control wiring, and blower operation before making the final module-side decision.
For more guided automotive diagnostics, visit STEP Diagnostics.
