OK, so when you manually energize the contactor, the unit works properly?

If so, I would pull and re-seat all of the low voltage connections relating to the contactor, the coil, low voltage cutoff switch (if equipped).

It sounds to me like poor voltage to the contactor.

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250