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My s430 is having intermittent issues with the heater motor blower I think I blew the heater motor blower when giving another car a jump start . The next few days after that I noticed that it wasn't blowing out hot air it kicked on before it crapped out a few times only on highway speeds . Thankfully the main auxiliary fan is still working and sends some hot air into the passenger cabin , the MIL light is on throwing a code for secondary air injection pump however I still think it's the motor blower fan that needs to be replaced. Does anyone have experience in this w220 heater motor blower diagnoses and replacement ? I think and I am pretty confident that I can do this job myself . I'm looking online at the parts for about 250$ is it safe to assume that the new resistor will come with the new motor blower fan assembly ???
Last edited by GOLDEN EYE W220; Dec 28, 2025 at 04:22 PM.
Reason: COMMUNITY
Doing a jump start has very little to no chance of damaging the HVAC blower.
If by main auxiliary fan you mean the radiator fan, it does not blow air into the car.
The secondary air injection pump has no connection at all with the HVAC system.
Check the blower fuse.
The HVAC blower is powered through an attached electronic control unit. You can access the blower motor fairly easily (Google or DuckDuckGo are your friends). You can then remove the electronic control unit and plug the heavy red power wire directly onto the fan motor. If the motor runs, the problem is likely to be the control unit. If not, the problem is likely to be the motor or the power to the red wire.
Doing a jump start has very little to no chance of damaging the HVAC blower.
If by main auxiliary fan you mean the radiator fan, it does not blow air into the car.
The secondary air injection pump has no connection at all with the HVAC system.
Check the blower fuse.
The HVAC blower is powered through an attached electronic control unit. You can access the blower motor fairly easily (Google or DuckDuckGo are your friends). You can then remove the electronic control unit and plug the heavy red power wire directly onto the fan motor. If the motor runs, the problem is likely to be the control unit. If not, the problem is likely to be the motor or the power to the red wire.
Hey wally good to hear from you . I disagree but as always I value your expert opinion and experience. I still think the motor blower resister was blown during the jump start . I have changed the 40 amp fuse to the heating and ac motor already along with the other two 40 amp fuses next to it . I'm going to look into a motor blower or controller unit I'll keep you posted .
wyrschper236@gmail.com
Last edited by GOLDEN EYE W220; Dec 30, 2025 at 06:37 AM.
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