W210 Climate Control Won't Shut Off (Have to Disconnect Battery)
Thread Starter
Newbie
Joined: Apr 2025
Posts: 2
Likes: 0
2002 E430
W210 Climate Control Won't Shut Off (Have to Disconnect Battery)
Hoping to hear from anyone whose diagnosed this previously.
My issue is that the Climate Control has recently become permanently on. Even when the climate controls are set to off, it still runs. Even when the key is off, it still runs.
Video for reference
Background:
Around a month ago I noticed my daughter's W210 (2002 e430) was having the A/C run even after the key was off. I thought maybe it was the "rest" feature and didn't think much of it at first. Then the battery went completely dead -- so I assumed it was related to the A/C blower running until the battery died.
I ended up replacing the "Blower Motor Regulator/Resistor" (AH-2108211551) since it seemed like that could be a common culprit. No issues since.
Today:
After a quick trip to the grocery store -- same thing -- blower is basically permanently on. I tried even pulling all the fuses in the engine bay, to no avail. Have to disconnect the battery to stop it. As soon as I reconnect, the blower is back on.
Could the regulator have gone bad that fast? Or do I need to start chasing a different gremlin?
I also pulled the codes from the climate control system (Eb1 234, Eb1, 235) -- but they don't seem to have any relation to what I'm experiencing.
Edit: As a stop-gap I've pulled the power plug to the blower motor.
My issue is that the Climate Control has recently become permanently on. Even when the climate controls are set to off, it still runs. Even when the key is off, it still runs.
Video for reference
Background:
Around a month ago I noticed my daughter's W210 (2002 e430) was having the A/C run even after the key was off. I thought maybe it was the "rest" feature and didn't think much of it at first. Then the battery went completely dead -- so I assumed it was related to the A/C blower running until the battery died.
I ended up replacing the "Blower Motor Regulator/Resistor" (AH-2108211551) since it seemed like that could be a common culprit. No issues since.
Today:
After a quick trip to the grocery store -- same thing -- blower is basically permanently on. I tried even pulling all the fuses in the engine bay, to no avail. Have to disconnect the battery to stop it. As soon as I reconnect, the blower is back on.
Could the regulator have gone bad that fast? Or do I need to start chasing a different gremlin?
I also pulled the codes from the climate control system (Eb1 234, Eb1, 235) -- but they don't seem to have any relation to what I'm experiencing.
Edit: As a stop-gap I've pulled the power plug to the blower motor.
Last edited by zongo; Apr 29, 2025 at 09:52 PM.
Member
Joined: Jun 2023
Posts: 178
Likes: 45
2000 E320
Scan the car. Not with generic OBD II cheap scanner but using 38-pin connector. Cheap OBD II scanner only shows engine codes. Get something like Foxwell NT530 or equivalent. If you don't want to buy it, find someone with equivalent scanner.
Finding the code from climate control only shows what's wrong with AC system, such as bad sensor. It won't show electrical gremlin.relating to the system. After you scan the car, get the code, look online for the code and if you still don't understand or can't seem to find the problem, come back here. Without it, we don't know where to begin.
Lastly, I'll share my experience with our W210. I have a 2000 E320. Our second one. When we acquired the car, it had bad instrument cluster. I bought the car that way, so I have no idea what was wrong with it. But all display won't show, and fuel gauge refused to work. Some back light didn't work. It also refused to turn itself off, even with key out from ignition switch. Also radio did the same thing. Climate control light refused to turn itself off (but climate control will turn off). Disconnect the offending cluster, everything turned off. Reconnect it, everything I mentioned stayed on. Got a used cluster from evilbay and connect the cluster, everything went back to normal.
In my case, I had pretty good idea what was wrong with it so I got it fix. Your case, scan the car first. Sounds like you have a electrical problem. 95% of the time, it WILL show up in scan.
Finding the code from climate control only shows what's wrong with AC system, such as bad sensor. It won't show electrical gremlin.relating to the system. After you scan the car, get the code, look online for the code and if you still don't understand or can't seem to find the problem, come back here. Without it, we don't know where to begin.
Lastly, I'll share my experience with our W210. I have a 2000 E320. Our second one. When we acquired the car, it had bad instrument cluster. I bought the car that way, so I have no idea what was wrong with it. But all display won't show, and fuel gauge refused to work. Some back light didn't work. It also refused to turn itself off, even with key out from ignition switch. Also radio did the same thing. Climate control light refused to turn itself off (but climate control will turn off). Disconnect the offending cluster, everything turned off. Reconnect it, everything I mentioned stayed on. Got a used cluster from evilbay and connect the cluster, everything went back to normal.
In my case, I had pretty good idea what was wrong with it so I got it fix. Your case, scan the car first. Sounds like you have a electrical problem. 95% of the time, it WILL show up in scan.
Thread Starter
Newbie
Joined: Apr 2025
Posts: 2
Likes: 0
2002 E430
Thank you for the tips. I hadn’t even realized gremlins like this could show on a scan. I’ll swing it by my Indy mechanic and see if they can’t run a scan for me.
Any chance a Napa or Autozome can run that scan?
Any chance a Napa or Autozome can run that scan?
Scan the car. Not with generic OBD II cheap scanner but using 38-pin connector. Cheap OBD II scanner only shows engine codes. Get something like Foxwell NT530 or equivalent. If you don't want to buy it, find someone with equivalent scanner.
Finding the code from climate control only shows what's wrong with AC system, such as bad sensor. It won't show electrical gremlin.relating to the system. After you scan the car, get the code, look online for the code and if you still don't understand or can't seem to find the problem, come back here. Without it, we don't know where to begin.
Lastly, I'll share my experience with our W210. I have a 2000 E320. Our second one. When we acquired the car, it had bad instrument cluster. I bought the car that way, so I have no idea what was wrong with it. But all display won't show, and fuel gauge refused to work. Some back light didn't work. It also refused to turn itself off, even with key out from ignition switch. Also radio did the same thing. Climate control light refused to turn itself off (but climate control will turn off). Disconnect the offending cluster, everything turned off. Reconnect it, everything I mentioned stayed on. Got a used cluster from evilbay and connect the cluster, everything went back to normal.
In my case, I had pretty good idea what was wrong with it so I got it fix. Your case, scan the car first. Sounds like you have a electrical problem. 95% of the time, it WILL show up in scan.
Finding the code from climate control only shows what's wrong with AC system, such as bad sensor. It won't show electrical gremlin.relating to the system. After you scan the car, get the code, look online for the code and if you still don't understand or can't seem to find the problem, come back here. Without it, we don't know where to begin.
Lastly, I'll share my experience with our W210. I have a 2000 E320. Our second one. When we acquired the car, it had bad instrument cluster. I bought the car that way, so I have no idea what was wrong with it. But all display won't show, and fuel gauge refused to work. Some back light didn't work. It also refused to turn itself off, even with key out from ignition switch. Also radio did the same thing. Climate control light refused to turn itself off (but climate control will turn off). Disconnect the offending cluster, everything turned off. Reconnect it, everything I mentioned stayed on. Got a used cluster from evilbay and connect the cluster, everything went back to normal.
In my case, I had pretty good idea what was wrong with it so I got it fix. Your case, scan the car first. Sounds like you have a electrical problem. 95% of the time, it WILL show up in scan.
