mak
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It can be used on any of the systems that use a Thermistor type CTS..The early 103 engines cars did not use thermistor, so they can not use this technique. You can tell on 103 cars b/c the sensor will be the 2 wire blu one. That is the applicable one. Here is the thermistor type sensor needed for mod.
http://catalog.peachparts.com/ShopByVehicle.epc?q=1990-Mercedes--Benz-300e--Base-Climate--Control&yearid=1990%40%401990&makeid=63%40%40MERCEDES+BENZ%40%40X&modelid=6194%3AMBC%7C1507%3AED%7C10000013%3ASM%7C20%3AEB%7C613%40%40300E+Base&catid=242213%40%40Climate+Control&subcatid=242256@@A%2FC+ACC+Temp+Sensor&mode=PA
If your chassis has that one , then you can do it. [ or the later 4 prong]
Go to Jim F site . He has taken this mod and made a connector that plugs right between the sensor and the connector and sells them.
And his menu has the info for both the early 2 wire and later 4.
Or, just get a film resistor and solder it across the connector plug.
You want a temp tolerant one, not carbon.
Seems like the new forums guys are not aware of this, but it is an old news around here ...just search 'Cool Harness' and there is tons of info from a few years ago.
A Note:
By adding this R across the thermistor/sensor , you do loose the default function of high fan if sensor fails b/c the CP does not see an open circuit b/c of the added parellel resistor...but that no big deal.
And yo do not want to go too low a cut-in b/c not only will the fans run all the time, but that same sensor is also the high temp cut-out for the compressor..I have seen ones that cut the comp off at high themal load before needed b/c the mod fooled the CP too much.
my recommend is anywhere near 100C cut-in for 104HFM. That shaves off 7C and seems to work fine w/o burdening the electrical system, etc...if that does not do the trick, you have something else wrong..like a bad viscous, thermo, or dirty condenser...etc...and covering that up by running the high aux fan at low cut-in temp is not the answer.
Benz claim is the 107 is fine, but we have found this mod to work better, and you will notice that the older mechanical Bens aux fan switches are 212F/100C...so .........................