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-   -   1994 E320 Aux fans (http://www.peachparts.com/shopforum/tech-help/221152-1994-e320-aux-fans.html)

outonmyboat 05-03-2008 01:15 PM

1994 E320 Aux fans
 
Can someone tell me where the sensor is that turns these fans on? They will run even when the car is cold. I am assuming it is a sensor that is bad!! Any help?

Arthur Dalton 05-03-2008 02:53 PM

There are two sensors..which speed are they staying ON ????

outonmyboat 05-04-2008 10:17 AM

Quote:

Originally Posted by Arthur Dalton (Post 1843032)
There are two sensors..which speed are they staying ON ????


High speed all the time.

stevebfl 05-04-2008 10:29 AM

The engine temp sensor has probably got a bad connection. Could be bad but the problem is often just the connection, wiggle it, unplug and replug it.

Arthur Dalton 05-04-2008 11:06 AM

As SB states, a a poor connection at that sensor will default the high fan to RUN.....
That sensor on that chassis it the blue, 2 wire one at the thermostat housing.
You can also test the circuit by unplugging that connector and bridging the 2 wires with a 1K ohm resistor...that will put the fan off if the circuit is OK..if not, then the suspect is a sticking high fan relay..that is under the panel [ 6 screws] behind the fuse box..the Green relay..

outonmyboat 05-04-2008 11:40 PM

OK I bridged the two wires @ 1k ohm resistance and the fans turned off. I checked the sending unit that the wires connect to and found when the sending unit is cold the circut is open when it's hot the same. Could this be a bad sending unit? I checked the sending unit with the wires off.

Arthur Dalton 05-05-2008 11:04 AM

Bad/Open sensor... The sensor is never open as it is a thermistor, so it always has a R value, temp dependent. If the ACC sees an open sensor, it defaults to full fan for engine overheat safety protection... [ your current condition]

http://catalog.worldpac.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=2AO123CS42D20NK27E&year=1994&make=MB&model=E-320-001&category=R&part=A%2FC+ACC+Temp+Sensor

outonmyboat 05-05-2008 09:17 PM

Thank You, Thank You, Thank You, I found a broken wire just inside the wiring harness. Works like a champ. Next on the fix it list. Any suggestions why my outdoor temperature gauge doesn't work. One day I looked at it and the numbers were gone.

Arthur Dalton 05-05-2008 09:22 PM

That chassis is infamous for bad engine wire harness..keep an eye on it..they fall apart.


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