|
Re: 1985 gmc radio questions
Yes, 15 amp is the correct size fuse for this circuit because it powers more than just the radio. This circuit also powers the 3 "ACC" (accessory) receptacles in the fuse box. Those are used to supply power to various options such as the 700R4 lock-up torque converter solenoid, 4 wheel drive indicator light, and auxiliary battery relay.
I can't find many details on the 700R4 wiring in the 1985 wiring diagrams but the 1986 diagrams have some info. It appears as though many of them have a switch inside the transmission that closes when the 4th clutch (overdrive) is engaged. That feeds power to the torque converter clutch solenoid which should have a resistance of 23.5Ω. So a short to ground in the wiring (internal to the trans) between that switch & the solenoid or a shorted solenoid are a couple possibilities that could cause the radio fuse to blow only when the trans is operated in overdrive.
|