What Jabaj007 did will work ok....in essense what i said previously, just tapping in at different locations. To answer Jabaj007's question, you don't want to bypass the temp sensor for the following reason:

If you wire the aux. fan to go on when the compressor goes on, the fan will cycle on and off with the compressor (obviously). The compressor normally cycles off when the refrigerant temp. reaches slightly above freezing (i forgot the exact temp)...this is done by the ETR Switch (electronic temp. relay??) located in the pass. side foot well with a temp probe just in front of the evaporator. This is done so that the evaporator will not accumulate ice and get blocked. So when this cycles the compressor off, your aux. fan will go off (if wired as we discussed). Now, another part of your AC system is trying to cool and condense refrigerant (the condenser). If refrigerant temps. at the rec/drier are high enough, the aux. fan will go on. When you are driving in stop and go traffic, or at idle, little or no air is moving across the condenser, so the temperature of refrigerant passing through the condensor will be too high...if high enough, the temp switch at the rec. drier closes thus turning on the aux. fan. There will be times when the compressor has cycled "OFF" due to cold temps at the evap. and there will be high temps at the rec. drier requiring auxilary cooling at the condensor. This is very important, because overall optimum functioning of the AC system is very heavily dependant on cooling and condensing refrigerant at the condensor (E.g. getting low side pressure as low as possible).

So, don't bypass the temp. switch.

With all that said, lets get back to the idea of having the aux. fan go on with the compressor. The only reason I did that (on my first 300D) was because I converted to R134 and wanted to optimize cooling/condensing at the condensor. Thus, I did not bipass the temp switch. (Note, I also installed a parallel flow condensor in place of the OE fin-tube type). On my current 300D I converted to R134, put in a parallel flow condenser, but decided not to wire the aux. fan to the compressor because I don't think there is any real benefit. The parallel flow condensor is a significant modification which enhances cooling/condensing sufficiently. Also, R134 gets "hotter sooner" than R-12, so with the aux. fan wired as designed to the temp switch at the rec. drier, it will cycle on more often with R134 than with R12.

Regarding the original line of discussion on this thread, the reason for wiring the aux. fan to the compressor, was because the temp switch apparently was not working....this is not really a valid reason...I recommend that the problem with the temp switch be troubleshooted (or troubleshot?) and fixed. Its a very simple circuit...if you jump the wires connected to the temp switch, the aux. fan should go on (if the ac system is on). If it doesnt go on, check the aux. fan relay. If it does go on, then check the temp. switch as previously described.

If the temp switch "broke off" due to the accident, there may be a little threaded stud left in the hole and will need to be removed.

Good luck,

Mark

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1984 300TD Wagon, 407,800 mi (current daily driver)
1985 300DT Sedan, 330,000 mi (gone to that great autobahn in the sky)