Hello all! I have a 1992 300CE (M104).

The car is a weekend cruiser, but with the territory of living in South Florida, it sees traffic. Just like a normal M104, it runs a bit on the warm side. I have yet to make the aux fans kick on, but I don't feel comfortable watching the temp creep up over 100C on the gauge in traffic. As soon as I start moving 30-40 mph, the gauge quickly falls back down to 85C-90C.

I've tested the fans and they work. A/C on high, they both spin, A/C on low one spins. Everything seems normal.

I just performed a cooling system maintenance too. Zerex G-05, 79C Behr thermostat, Red Line Water Wetter, and a new reservoir cap. I'm at about 70% coolant 30% distilled water. There aren't overheating issues, I just want some insurance. The cool harness looks great, but I have a hard time justifying the $90.

I picked up a pack of resistors and went to town. 2.2k 1/2w Radio Shack flavored resistors. I spliced into my CTS wires and soldered them up (see pic 1). Followed it with heat shrink tubing. Is it okay that I spliced the resistor this way?

Now the problem, the mod didn't work. From what I've read in other threads on here and other forums; this resistor should "trick" the fans into turning on at about 98C.

I did the mod, buttoned things back up, drove the car around for about 30 minutes, let it sit idling for 30 minutes (keeping a close eye on it), the gauge crept up over 100C (see pic 2), nothing. Didn't quite get hot enough for the fans to kick on, so I just shut her down. Let it heat soak for 10 minutes, started it back up, fans kicked on right away and brought the car down to 85C as they should.

Looking for some guidance here. Don't think I could've plugged the CTS plug in backwards.. Any help is greatly appreciated.

Thanks
Nicholas