The other day, my ’87 300E starting blowing fuse #7 when I turn the A/C on. Everything on the car works great until I engage the A/C and then the fuse pops. I scoured the A/C threads here and ran some diagnostics based on what I read (thank you Brian C). Here’s where I’m at:

1. PBU and auxiliary pump are relatively new and working.
2. The inputs to the Klima socket have the correct values per Saumil Patel’s 50 item test.
3. The compressor will engage when I jumper sockets 5 and 7 at the Klima relay. Cool air will blow, but the wires get hot.
4. Currently, I have an “ice cube” relay installed in place of the Klima (trying to narrow this down).
5. I removed the connector at the compressor and hooked up just the wire for the clutch control output (blue/green). Probably doesn’t affect much since I’m using the “ice cube”, but I wanted to eliminate as much as possible. With a 30 amp fuse, the A/C works fine (just ran for several seconds to verify). 15 amp fuse will blow.
6. Now… I noticed that one of the wires that go to the speed sensor on the back of the compressor is exposed and a bit frayed. I did some continuity testing and neither wire seems to go to ground. Also, when I tested across pins 9 and 11 at the relay, I got 650 ohms resistance and .3 volts when I engaged the compressor, which seems to be correct for the speed sensor (prior to pulling connector at compressor).

Does anyone know if there is a way to disconnect the speed sensor at the compressor in order to take that out of the equation completely? Also, am I on the right track in thinking that there is an electrical problem at the compressor, or should I be testing somewhere else as well?

Thanks in advance for any help. I'm out of ideas.