Cluster ground G204 (located near center console) is shared by multiple devices including the GEM, cruise control, Cluster, AC blower motor, and the RADIO. The ground is frequently messed up during a radio install.
Start by pulling the cluster. Clean the electrical harness connector with electrical contact cleaner. Lightly re-grease with silcone di-electric grease (same kind as used on spark plugs).
Measure the key off resistance between the cluster Black wire (pin #20) and battery negative. Post. Repeat with the BK/WH wire (pin#1) and battery negative. Post. If the resistance is high (above 5 Ohm), there is a poor ground path that needs to be addressed.
Test for key on +12 volts between the following cluster pins and the cluster BK wire. Be careful during testing to not short out any pins.
Color pin# fuse
RD/WH #10 F2.21
PK/BK #11 F2.5
WH/LB #12 F2.34
LB/RD #04 F2.37