Hello and welcome to Just answer.com, Super mechanic here. About your vehicle.
There has been a service bulletin for that type of concern. It could be the controller but you will want to have the reprogramming done or checked on it first.
Here is what it states.
NUMBER: 24-002-04 REV. A
GROUP: Heating & A/C
DATE: July 30, 2004
THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN 24-002-04, DATED MARCH 30, 2004, WHICH SHOULD BE REMOVED FROM YOUR FILES . ALL REVISIONS ARE HIGHLIGHTED WITH **ASTERISKS** AND INCLUDES ADDITIONAL MODEL YEAR.
SUBJECT:A/C and Heater Performance
This bulletin provides diagnostic information for A/C and heater performance complaints.
NOTE :Perform Customer Satisfaction Notification no. 857, reprogram Powertrain Control Module (PCM), for 2000 model year LH-vehicles built prior to August 30, 1999 (MDH 0830XX).
Erratic operation of the A/C and heater systems including:
The above Symptoms may be accompanied by the following Diagnostic Trouble Codes (DTCs):
POLICY:Reimbursable within the provisions of the warranty.