Electrical burning smell from 1994 E420
 

Today, I was allowing my car to just sit and idle while I went inside the store. As I came back to the car I notice a electrical burning smell in the air. I thought at first it must be a car passing by so I ignored it. About 20 minites later I got out of the car and notice the electrical burning smell again. So this time I pop the hood to try and pin point this oder. I finally discover where the smell was coming from. Under the hood behind the driverside headlight, below the ABS pump. It has a metal coil wire in the center of a metal cover. Can someone tell me what it is and what it does. It has a red or orange wire going to it. Sorry Forum will not allow me to upload any photo. The forum site tell me each time file to large. Thank for any help in advance.

Aux fan pre-resistor for low speed a/c condenser fan.

Look for bad connections at each terminal.

Common fail part.

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1LN0ST6SC1LW17E8C9&year=1994&make=MB&model=E-420-001&category=G&part=Aux.+Fan+Resistor

Electrical burning smell from 1994 E420
 

That is it!!! Since it is a common problem is it better to replace the resistor due to age and extreme heat or do I need to trouble shoot it. Thanks again.

The wireing usually fatigues with age/heat, but it is best to make sure the fans are free and not drawing too much power to see if high amp draw is the cause.
Both fans on high should not exceed 25A.

Electrical burning smell from 1994 E420
 

Arthur thanks for your quick reply. I will take a look at the fan and test the amp. I will post my results.

An easy draw test is to pull the fuse from the high fan relay and put the Amp meter across those terminals.. that gives you an easy access series circuit for the meter w/o having to do any wire disconnects.
The relay is behind the fuse box .. high fan will be the one with the 30A fuse on top. Circuit activation is key ON and pull 2 wire connector at ECT switch/sensor at thermo housing [ blue 2 wire sensor].. this acivates high fan by default...
Another way is to jumper from bat+ w/ amp meter in series, to the terminal of the resistor with the 2 wires on that terminal.
This will be a direct draw test bypassing key sw and sensor.
Either /Or

Thanks Arthur
 

For some reason I posted a update two months ago and it never post. Anyway I would like to thank you Arthur for your help in solving my problem. In deed it was the Aux Fan Resistor. I replace the resistor and that took care of the problem. Thanks

Cool... Thanks for the closure.