SoCal,

I will check too. And I do have a relay-I just used a wire with a fuse in it to test the compressor-I wanted to eliminate all other variables (switch, relay, and wiring). But, even with the car running, the alarm siren hooked up to the PW post was not working last night (it did in the morning). There must be some hidden circuit breaker somewhere in the system. (I even checked my test light on another car to see if the bulb was burnt out.)

If that fuse block wasn't working, though, nothing else in the car would work.

Well, I checked the fuse block and both posts with the engine running-and still no power. What feeds this block? And what feeds the jumpstart post? All of the accessories in the car seem to be working, so the block must be getting power!

Could have cooked a wire in the UBEC and now have an open in just that circuit. If I get a sec I'll pull a schematic thsi afternoon, pretty slow today I only have 2 more jobs to look at.

Thanks Aaron. What is the UBEC? Shouldn't it be able to handle an airhorn-less than 20 Amps. And why wouldn't the fuse blow?

There is a 50 amp fuse inline between the battery and the fuse block. It should be in the rear near the battery. Check that.

I already checked that the other day, and it is good. In fact when I removed it, everything in the car went dead (interior lights, radio clock, etc.)

What's next?

Do you have power across the EPS fuse? I think it is number 1 in the block, it is a J-fuse, either 30 or 60 amps.

Something is really crazy. I checked the fuse with a continuity tester and it is good. I checked both terminals and neither had 12 volts. I did this with the engine running. Yet, when I tried turning the steering wheel with the fuse pulled, there was no power steering. With the fuse replaced, the power steering worked again. How could this be with no power at the fuse block???

Pop the cover off the fuse and test with a test light at both terminals, then check a few of the other fuses just to verify power across them. I've seen those J-fues blow, but still allow power across them due to the funny design. When they blow the pieces are still contacting each other.

More wierd stuff. I checked this morning and everything is showing 12 volts-alarm siren working and everything. Even the jumpstart pole has power. But, when I tried connecting my airhorns to it, you could just hear a weak sound from the compressor, even when I bypassed the relay. Apparantly it does not have enough amperage. Next question-where can I tap in for power for the new horns? There are several empty fuse slots in the box-could I just attach a spade terminal and plug in to one? (Obviously I am running an inline 20 amp fuse). If so, does it matter which one?

Again, thanks for all the suggestions and help.