Troubleshooting Hints - Front Heater - Without A/C

^ CHECK that either the A/C MAXI FUSE or the HTR - A/C (Fuse 12) is not open. If either fuse is open, LOCATE and REPAIR source of overload and REPLACE the Fuse(s).
^ CHECK that Grounds G100, G106, G200, and G301 are clean and tight.
^ CHECK that Blower Motor Resistor and Relay Pack is properly mated to its connector.
^ CHECK for a broken (or partially broken) wire inside of the insulation which could cause system malfunction but prove GOOD in a Continuity/Voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a voltage drop with the system operational (under load).
^ CHECK for proper installation of aftermarket electronic equipment which may affect the integrity of other systems (See Diagnostic Aids for General Troubleshooting Procedures). Diagnostic Aids