The resistance sounds way high. I don't have the exact specification handy, but something in the vicinity of 5 ohms is about where you want to be. The coil draws a couple of amps current - you can use ohms law to determine where the resistance needs to be. I suggest you try measuring just the clutch coil directly at the compressor terminals.

Are you sure about the wiring and operation of the compressor circuitry? I'm familiar with the 124 of the same vintage, but have the (probably mistaken) impression the 126 is similar. On that car, the signal from the PBU passes through the pressure switch on its way to the Klima relay. To measure clutch coil resistance you pull the Klima relay and measure from that point. Fastlane lists a Klima relay for your car, so I think I'm on the right track here.

Can the clutch be replaced in situ? Probably. On a 124 with the OM603 it can be done, but requires either a veerrrry low profile clutch removal tool, or pulling the radiator. I'd imagine there's more room to work on the 126. Worst case, plan to pull the radiator. Yeah, it's a pain, but cheaper and easier than dealing with refrigerant issues.

- JimY