Sluggo

I just pulled one of the rear deck speakers from my 92 SC4 and it measures open on the ohmmeter. These things are not bulletproof. If you have access to a voltmeter (a $10 radio shack works fine), just put it across the speaker terminals and check for a signal when you have the volume turned up and a speaker attached. If you have signal and no sound, bad speaker. No signal, bad amp.

I had a coast-down vibration problem between 35 and 30 mph. Turned out to be a tranny mount, which is apparently a not-uncommon problem in these cars. PS Mine also a 92 SC400 with about 130k on the clock.

If there is a "hole" in one of the black "boxes", then you probably have found the source of your problem. The "boxes" are the output transistors for the individual amplifiers in your multichannel amp. A "hole" is caused when the transistor die get so hot that it literally blows the plastic packaging material (the black stuff) out, leaving a little crater. The transistor probably got hot because it failed (shorted) internally, and so the +14.4 Volt supply got shorted to ground. This allows a buttload of current through the device, heating it up to the point that it blew out the packaging. The failed transistor probably remains shorted, and this is why you are blowing fuses. Remove that transistor from the amp, or simply cut it's leads so that it has no electrical connection to the circuit. New speakers, if they were of a lower impedance then the old speakers, may have caused the overheating of a weakened transistor.

The control arm itself does not wear out, it's just the rubber bushing that provides the mounting point that wears out. And at 102k miles, they are probably gone, even though they may look okay on an inspection. Toyota does not supply bushings as a separate item, they will only provide an entire new control arm (with bushing already installed) for repairs. There are suppliers who will see you the bushings alone. You can take these to most any suspension shop and they can remove your current control arms, take out the old bushings and press in the new ones. Replacement bushings can be very inexpensive (~$100 for a full set), but these tend to be pretty hard and can squeak a lot. There's a guy in Australia who makes a very good set of rubber bushings, but these are on the pricey side (~$1000). Check PlanetSoarer for more info.

There are a couple of these on a very, very large auction site right now.