HELP! 1997 E300 Diesel aux fan doesn't turn on

[Riad]

Replaced the bad original fan with this one: Depo 340-55002-200 Condensor Fan Assembly but the fan won't come on . Checked the climate control setting for the fan (left side 20 right side 10). Checked the volt on the (female) connector (that connects to the fan) and it gives me zero voltage. So assuming I need to replace the aux fan control module for my car (N65/1?), where exactly is it for the 1997 E300 Diesel? There's nothing under the driver side headlamp. There's black box sort of behind the headlamp. Is that the one?

Thanks!

[Dmitry at Pelican Parts]

Hello Riad - take a look at the link below to hopefully address the aux cooling fan. If you have any further questions, feel free to post a Comment just below the article and one of our techs will get back to you with details.

Mercedes-Benz W210 Auxiliary Cooling Fan Belt Replacement (1996-03) E320, E420 | Pelican Parts DIY Maintenance Article

[nelbur]

The auxiliary fan is normally off. It comes on low when the A/C is turned on, and will run at high speed if the engine temperature gets high, but don't remember how hot it has to get to turn it on. Are you sure it does not run at low speed with the A/C on?

[ah-kay]

How did you determine the original one was bad?

The easiest way to turn it on at slow speed is to jump the high pressure switch at the recv/driver. It will be on when you turn the key. You can turn it on at high speed but you need to jump the thermostat at the top of the radiator hose. I am not familiar with your car to give you which connector to jump.

[tjts1]

Originally Posted by nelbur

The auxiliary fan is normally off. It comes on low when the A/C is turned on, and will run at high speed if the engine temperature gets high, but don't remember how hot it has to get to turn it on. Are you sure it does not run at low speed with the A/C on?

The w210 fan is PWM controlled so there's no low/high. It can vary it's speed as needed. It's triggered by a pressure sensor in the AC as well as a temperature input from the engine. I think 17bar and 105c going from memory.