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Garage => Mechanicals => Topic started by: rob280 on 10 May 2019, 10:06 AM

Title: No high blower speed
Post by: rob280 on 10 May 2019, 10:06 AM
My 280S has the auto climate control with the ACCII upgrade kit. It works but the blower speed is always slow, even on high it is slow. What should I look for?
Title: Re: No high blower speed
Post by: Diesel 617 on 11 May 2019, 06:36 AM
Sounds like your blower relay is on its way out. Pull out the glove box and next to where the amplifier would be there is a small sliver box with a plug attached to it. Remove it and buy a 100% Genuine replacement. Do not go with the Bosch or any non Mercedes part it wont work.
Title: Re: No high blower speed
Post by: rob280 on 12 May 2019, 10:45 AM
Diesel 617,

That relay is working, the fan speed increases when I press DEF. I hear the relay clicking, and DEF will not work without the relay plugged int. The fan speed just seems low on Auto-HI, the fan does slow down when I push Auto-LO.
Title: Re: No high blower speed
Post by: daantjie on 12 May 2019, 10:38 PM
Could be the blower resistor.  It's in the fresh air intake section. You have to remove the chrome grill to acess it after you remove the wiper arms.
Title: Re: No high blower speed
Post by: Squiggle Dog on 13 May 2019, 11:24 AM
Could be the blower resistor.  It's in the fresh air intake section. You have to remove the chrome grill to acess it after you remove the wiper arms.

You can also access it by reaching up into the opening above where the blower motor housing attaches once the housing is removed and you have the screws securing the resistor to the firewall removed.  For installation, though, you'll have to reach back up in there and push it into place so you can carefully attach the screws without pushing it back in. You can decide which method is more convenient for you.
Title: Re: No high blower speed
Post by: thegreg92 on 16 May 2019, 09:43 PM
The blower only runs at max speed on the defrost setting, bypassing the resistor pack. The high or low settings will run thru the various stages in the resistor pack.

I’ve had luck wiring up a relay for the blower that bypasses the resistor when using the high and low settings. Def a game changer in the Arizona summers