Strange W124 auxiliary fan problem, high speed constant

[David Hendy]

I'm working on a '94 E320 that has a strange aux fan issue.

Its an earlier car with the separate gauge sender and blue two pin fan sender. The aux fans come on at high speed as soon as the ignition is turned on.

The fans cut off when I remove fuse 7 or the single pole sender connection.

The car has a recently replaced engine wiring harness.

I replaced both the high speed and low speed relays and the blue two pin sender. The fans still run on high speed regardless.

Also the temp gauge does not work.

Thoughts? Bad ECU?