Radio - AM Noise
Model Year 1983Bulletin No. 83-59
File in Group 90
Number 4
Date Feb., 83
SUBJECT: AM Radio Noise - 1983 Models With Diesel Engines
Some 1983 vehicles equipped with a diesel engine may experience AM radio noise during part throttle operation with the TCC engaged. This noise, which sounds like "ignition" noise (a cracking, buzz noise) may be caused by vibrating or bouncing contacts in the vacuum regulator valve.
Replacing the vacuum regulator valve with one that has a Julian date stamp of 25321, or later, will correct this condition. The Julian date is stamped on the outboard side of the VRV. Refer to illustration for example.