GM Service Manual Online
For 1990-2009 cars only

Driver Information Center (DIC) or Message Center Circuit Description for Chevrolet Astro - 4WD 1998

The compass and temperature display module contains the entire compass display circuitry. Refer to Electronic Compass Calibration in order to set the variance. The speed signal CKT 389 (DK GRN) must be present in order to accurately diagnose the compass and temperature display module.