- Checked resistance of compressor clutch voltage supply line - 0.5 ohms; line is intact.

- Applied 12.4v to clutch supply line... 12.4 volts present at the end of the line. Again, line is intact and there is no parasitic loss.

- Connected the voltage supply line to the compressor clutch and applied voltage - clutch is activated.

So, with the vehicle's original PBCU (210 830 22 85) installed, the voltage out from pin 25 is only 8 volts.

Is PBCU renewal warranted?

Installed a used PBCU from a 98 E 300D (210 830 32 85) that was functional when originally removed; clutch activation voltage remains at 8 volts.