Smart Roadster HVAC System Multiple Failures & Fixes

Had a very similar issue with my Smart ForTwo (2005) last winter. Have some experience working on basic car maintenance but electrical problems are trickier. The symptoms matched exactly, weak blower motor, temperature sensor giving false readings, and climate control panel acting up. After trying basic troubleshooting like checking fuses, I took it to my regular workshop. The diagnostic revealed loose connections in the main wiring harness going to the climate control unit. The technician found that vibration over time had caused some pins in the connector to lose proper contact. The repair involved cleaning the connections and securing the plug properly. Total cost was 95€ including diagnostic and labor. The electronic faults disappeared completely after fixing the connection issue. The air conditioning and heating both work perfectly now, and the blower motor returned to full power. What engine variant does your Roadster have? Also, can you share if the climate control panel is completely dead or just partially responding? This would help determine if your issue is similar to what I experienced. Another thing to check, does the fault happen more when driving over bumpy roads? This could indicate a loose connection like in my case.

Had a very similar issue with my Smart ForTwo (2005) last winter. Have some experience working on basic car maintenance but electrical problems are trickier. The symptoms matched exactly, weak blower motor, temperature sensor giving false readings, and climate control panel acting up. After trying basic troubleshooting like checking fuses, I took it to my regular workshop. The diagnostic revealed loose connections in the main wiring harness going to the climate control unit. The technician found that vibration over time had caused some pins in the connector to lose proper contact. The repair involved cleaning the connections and securing the plug properly. Total cost was 95€ including diagnostic and labor. The electronic faults disappeared completely after fixing the connection issue. The air conditioning and heating both work perfectly now, and the blower motor returned to full power. What engine variant does your Roadster have? Also, can you share if the climate control panel is completely dead or just partially responding? This would help determine if your issue is similar to what I experienced. Another thing to check, does the fault happen more when driving over bumpy roads? This could indicate a loose connection like in my case.

Had a very similar issue with my Smart ForTwo (2005) last winter. Have some experience working on basic car maintenance but electrical problems are trickier. The symptoms matched exactly, weak blower motor, temperature sensor giving false readings, and climate control panel acting up. After trying basic troubleshooting like checking fuses, I took it to my regular workshop. The diagnostic revealed loose connections in the main wiring harness going to the climate control unit. The technician found that vibration over time had caused some pins in the connector to lose proper contact. The repair involved cleaning the connections and securing the plug properly. Total cost was 95€ including diagnostic and labor. The electronic faults disappeared completely after fixing the connection issue. The air conditioning and heating both work perfectly now, and the blower motor returned to full power. What engine variant does your Roadster have? Also, can you share if the climate control panel is completely dead or just partially responding? This would help determine if your issue is similar to what I experienced. Another thing to check, does the fault happen more when driving over bumpy roads? This could indicate a loose connection like in my case.

Thanks for sharing your experience. Our issues sound quite similar. My model has the 698cc turbo engine. The control panel works intermittently, sometimes completely dead, other times it responds but the settings dont actually change anything. The blower motor behavior definitely gets worse on rough surfaces, which matches your wiring harness theory. Given that my car shows 93762 KM on the odometer, those electrical connectors could well have worked loose over time. Good to hear your fix was relatively straightforward and cost-effective. Will have the temperature sensor connections checked too since that could explain the heating problems. Will book it in to have the wiring inspected based on your feedback.

Thanks for sharing your experience. Our issues sound quite similar. My model has the 698cc turbo engine. The control panel works intermittently, sometimes completely dead, other times it responds but the settings dont actually change anything. The blower motor behavior definitely gets worse on rough surfaces, which matches your wiring harness theory. Given that my car shows 93762 KM on the odometer, those electrical connectors could well have worked loose over time. Good to hear your fix was relatively straightforward and cost-effective. Will have the temperature sensor connections checked too since that could explain the heating problems. Will book it in to have the wiring inspected based on your feedback.

Thanks for sharing your experience. Our issues sound quite similar. My model has the 698cc turbo engine. The control panel works intermittently, sometimes completely dead, other times it responds but the settings dont actually change anything. The blower motor behavior definitely gets worse on rough surfaces, which matches your wiring harness theory. Given that my car shows 93762 KM on the odometer, those electrical connectors could well have worked loose over time. Good to hear your fix was relatively straightforward and cost-effective. Will have the temperature sensor connections checked too since that could explain the heating problems. Will book it in to have the wiring inspected based on your feedback.

Good to hear your symptoms match my ForTwo case, especially the connection between rough roads and system behavior. The similar engine setup in these cars means the wiring routing is nearly identical. The intermittent control panel response combined with the mileage strongly points to wiring harness issues. When we fixed mine, the technician found that the temperature sensor connections had oxidized over time, causing erratic readings that confused the climate control system. One tip from my repair, have them check the power supply connections to the blower motor while theyre in there. In my case, the same vibration that loosened the main harness had affected the blower wiring too, causing the weak airflow. The electronic faults in these systems often trace back to connection problems rather than failed components. Given your description of the symptoms getting worse on bumpy roads, Id bet youre dealing with the same core issue. The repair should be similarly straightforward if thats the case. Let us know what they find when you get it checked. These climate control problems can be frustrating but are usually fixable without major parts replacement.

Good to hear your symptoms match my ForTwo case, especially the connection between rough roads and system behavior. The similar engine setup in these cars means the wiring routing is nearly identical. The intermittent control panel response combined with the mileage strongly points to wiring harness issues. When we fixed mine, the technician found that the temperature sensor connections had oxidized over time, causing erratic readings that confused the climate control system. One tip from my repair, have them check the power supply connections to the blower motor while theyre in there. In my case, the same vibration that loosened the main harness had affected the blower wiring too, causing the weak airflow. The electronic faults in these systems often trace back to connection problems rather than failed components. Given your description of the symptoms getting worse on bumpy roads, Id bet youre dealing with the same core issue. The repair should be similarly straightforward if thats the case. Let us know what they find when you get it checked. These climate control problems can be frustrating but are usually fixable without major parts replacement.

Good to hear your symptoms match my ForTwo case, especially the connection between rough roads and system behavior. The similar engine setup in these cars means the wiring routing is nearly identical. The intermittent control panel response combined with the mileage strongly points to wiring harness issues. When we fixed mine, the technician found that the temperature sensor connections had oxidized over time, causing erratic readings that confused the climate control system. One tip from my repair, have them check the power supply connections to the blower motor while theyre in there. In my case, the same vibration that loosened the main harness had affected the blower wiring too, causing the weak airflow. The electronic faults in these systems often trace back to connection problems rather than failed components. Given your description of the symptoms getting worse on bumpy roads, Id bet youre dealing with the same core issue. The repair should be similarly straightforward if thats the case. Let us know what they find when you get it checked. These climate control problems can be frustrating but are usually fixable without major parts replacement.

My engine is indeed the 698cc turbo. Your experience has been really helpful in narrowing down the likely cause. The control panel symptoms match exactly what you described, sometimes completely unresponsive, other times just partly working. And yes, the blower motor definitely acts up more on bumpy roads just like in your case. The vibration connection makes perfect sense. My cars odometer shows 93762 KM now, so the wiring harness has had plenty of time to work loose. The connection between rough roads and system issues really points to your diagnosis. Good to know about checking both the temperature sensor and blower motor connections while inspecting the main harness. The air conditioning and heating problems being caused by loose connections rather than failed parts is encouraging. Based on your experience, I will schedule an inspection focused on the wiring and electronic faults first rather than assuming worse component failures. Thanks for the detailed insight. Will update once I get the connections checked and hopefully its a similarly straightforward fix like yours was.

My engine is indeed the 698cc turbo. Your experience has been really helpful in narrowing down the likely cause. The control panel symptoms match exactly what you described, sometimes completely unresponsive, other times just partly working. And yes, the blower motor definitely acts up more on bumpy roads just like in your case. The vibration connection makes perfect sense. My cars odometer shows 93762 KM now, so the wiring harness has had plenty of time to work loose. The connection between rough roads and system issues really points to your diagnosis. Good to know about checking both the temperature sensor and blower motor connections while inspecting the main harness. The air conditioning and heating problems being caused by loose connections rather than failed parts is encouraging. Based on your experience, I will schedule an inspection focused on the wiring and electronic faults first rather than assuming worse component failures. Thanks for the detailed insight. Will update once I get the connections checked and hopefully its a similarly straightforward fix like yours was.

My engine is indeed the 698cc turbo. Your experience has been really helpful in narrowing down the likely cause. The control panel symptoms match exactly what you described, sometimes completely unresponsive, other times just partly working. And yes, the blower motor definitely acts up more on bumpy roads just like in your case. The vibration connection makes perfect sense. My cars odometer shows 93762 KM now, so the wiring harness has had plenty of time to work loose. The connection between rough roads and system issues really points to your diagnosis. Good to know about checking both the temperature sensor and blower motor connections while inspecting the main harness. The air conditioning and heating problems being caused by loose connections rather than failed parts is encouraging. Based on your experience, I will schedule an inspection focused on the wiring and electronic faults first rather than assuming worse component failures. Thanks for the detailed insight. Will update once I get the connections checked and hopefully its a similarly straightforward fix like yours was.