engine temp vs. ACC sensor - PeachParts Mercedes-Benz Forum

d.delano · #1 09-29-2009, 11:16 PM

1993 190E 2.6 M103 engine

I have a sensor between the air cleaner box and valve cover on the driver's side, looks like a blue two-connector. Which is this? Also, where would the green 3-prong engine temp sensor be located? I need to stop the aux fans from spinning on high intermittently, and have been advised these may be culprits. Any advice on using a voltmeter to troubleshoot these? I'd rather see if they are bad before replacing them. I have a voltmeter, but wouldn't know what to set the selector to or what values to consider when testing these sensors. Thanks

mbdoc · #2 09-30-2009, 08:26 AM

Aux fan sensor on that car is a blue 2 pole sensor

d.delano · #3 09-30-2009, 01:01 PM

alright, thanks - so where is the green 3-pole sensor located? Can't find it

JimF · #4 09-30-2009, 04:38 PM

Quote:

Originally Posted by d.delano

1993 190E 2.6 M103 engine

I have a sensor between the air cleaner box and valve cover on the driver's side, looks like a blue two-connector.

As MB-Doc stated, that is the Aux Fan sensor.

Quote:

Originally Posted by d.delano

I need to stop the aux fans from spinning on high intermittently, and have been advised these may be culprits.

Culprit?? If the A/Fans spin, high or otherwise, it's b/c they NEED TO! There's nothing wrong. Menu#18 shows how the sensor works w/ the A/C and Aux Fans.

d.delano · #5 09-30-2009, 05:27 PM

Quote:

Originally Posted by JimF

As MB-Doc stated, that is the Aux Fan sensor.

Culprit?? If the A/F spin, high or outwise, it's b/c the NEED TO! There's nothing wrong. Menu#18 shows how the sensor works w/ the A/C and Aux Fans.

Thanks Jim but as I stated it's an intermittent on/off when the engine temp is normal, as if somebody is getting their jollies flipping a switch on and off. Definitely not normal. Now - where is that green 3-prong engine temp sensor located again?

JimF · #6 10-01-2009, 01:46 AM

Is the A/C on? If so, then it's normal since a burst of high pressure causes the second part of the ckt electronics (pressure switch on the rcvr-dryer) to turn the aux fan on to cool the evaporator even though engine temp is normal.

My 190E did that alot!

long-gone · #7 10-01-2009, 05:09 AM

My aux fans would go on and off randomly, normal temp, no A/C. I replaced the blue/two-prong sensor and it all works fine now. I don't have a three-prong sensor on my 91 2.6. Can't help you there.

d.delano · #8 10-01-2009, 12:12 PM

Quote:

Originally Posted by long-gone

My aux fans would go on and off randomly, normal temp, no A/C. I replaced the blue/two-prong sensor and it all works fine now. I don't have a three-prong sensor on my 91 2.6. Can't help you there.

That's what mine does - so I guess testing would be a waste of time. I'll just get a new one.

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