Replacing Heater Controller ECU - Smart Fortwo 451 Passion 84 BHP - Poor Temperature Regulation

The heater controller contains an ECU and a failure within, usually the rheostat (variable resister) can cause issues where the interior temperature is poorly regulated by the HVAC system, which is a basic form of climate control. This setup is used on the Smart Fortwo 451 Pure/Pulse/Passion/Brabus and limited editions. Some basic models will not have the air conditioning (A/C). My vehicle is a 2008
In this video I replace the heater controller with a second hand/used part. This involves removal of some dashboard trims and the radio.
Part number: A4519000901
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Disclaimer - Please be advised that my videos are not instructional and are merely footage of me, with many years of motor trade experience, carrying out vehicle repairs and maintenance. Please conduct your own research, ensure you have the correct tools/necessary expertise and undertake your own due diligence before carrying out vehicle repairs. If in doubt, entrust an automotive technician / car mechanic.

[@JohnMonaghan-uv6nm]

Great video again, every detail shown making life easier for us. Mine had the 3lines on the dash but your video on the earth strap to the engine and cleaning it fixed mine , 300miles on and its perfect, thanks.

[@WizardsToenail]

Love your videos I'm a new subscriber, hopefully getting my first smart fortwo on Sunday (if I haven't been scammed). Your videos have been a great help in decision making. I'm quite practical and do basic to intermediate jobs on cars so I will be referring to your videos if needed in the future.

[@brianlynch2512]

Thanks for your videos, very detailed and I love it!

[@mariokibys]

Thank you for your great work, I enjoy every video of yours.

[@WBSoCal]

I will be looking forward to see if that solves your problem. I similarly have the same issue. I was told that it might be the thermistor down below in the air duct that could be causing the problem.

[@Jaxs2]

Just the job 👌

[@jimmyadams628]

You're THE MAN 😊

[@michaelglynn2638]

Good job. Good filming too! 👍

[@jurgenberg5941]

Danke, wieder ein interessantes Video! Viel Erfolg mit dem Getriebe-Stellmotor. Gruß Jürgen

[@darrenfox5883]

Thank you for posting this. I am having the opposite issue in that almost any setting off of the bottom is nearly full heat. I wonder if it is possible to get into the unit to see if the problem with the variable resistor is repairable?

[@91strelok]

Hey I see your radio volume button is the same as ours (paint is sticky and falling apart). We recently wiped it with paint thinner and ours is now completely white :D Unfortunately the button is longer than it seems and has an edge keeping it from pulling it out. I am going to take apart the radio and paint the button with some durable paint, but hey, in case you are willing to go trough this venture before us let us know.

[@tine8849]

Well this sounds familiar. I had this problem when winter hit hard a few weeks ago. I also had my AC regassed last summer and it would blow cold for bit but stopped, so I thought I had a leak but occasionally out of nowhere it'd blow cold. I wonder if this was the issue.

[@benellias87]

I have a facelift 451 the dash seems to be one solid bit, any ideas how to remove a climate control..?

[@Quickblood1]

Is there anyway to ensure this is the issue or the new used part doesn't have the same problem?

[@autoknight747]

If the part is used then you are rather at the mercy of the seller. My old HVAC control unit was actually showing a fault code stating it was defective. That’s pretty conclusive!

[@Quickblood1]

@@autoknight747 Brilliant thanks, I'll have a look to see if I've got a fault code. Ta