Of course once you have done this, the compressor comes on whenever the key is on so it by-passes all the other problems that could be there. Not much good for diagnostics.
The problem with by-passing just the speed signal is that it is a dynamic pulsed signal and it is being compared in the electronics to the engine speed. It isn't a given at any particular time so it would be hard to reproduce and since the two signal aren't the same form (one is AC and one is DC they can't be just duplicated for comparison.
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician
[This message has been edited by Webmaster (edited 03-17-2000).]