I agree with ichris93—sounds like a low-voltage problem. If the battery itself is OK, check the battery wires, the main distribution block squeezed in between the battery and the shock tower, and the main engine-chassis ground cable (underneath the car at one of the transmission mounting bolts). If the cars cranks and starts easily then it's probably not that part of the wiring, the heavy stuff. In that case, check the add-on 30A strip fuse for the blower and all of the fuses in the fuse/relay box. Don't just look at them, remove each one, make sure the ends are not corroded and check the fuse clips too. If any of the fuses are aluminum change them to copper.

Jeremy

EDIT: If the tach works it's not the OVP relay.

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970