Ground Circuit Checks
WARNING: This page is about a different car, the 1994 Volvo 960, 1994 Volvo 940, and 1994 Volvo 850. However, it is still accessible from the selected car via links, so may be relevant.
Turn ignition off. Connect an ohmmeter between ground and measuring unit terminals No. 19, 24, 26, 30,and 48. Ohmmeter should indicate about zero ohms in all cases.