Help needed re: instruments/gauges on my 1995 993 cabriolet, which are working intermittently (usually not at startup, then come on either seconds later or up to 5 minutes later, seemingly after alternator has charged up battery). My local shop thought it was the ignition switch and say they replaced it, however, the problem is still occurring intermittently. Battery light is coming on at startup, indicating that the battery is being drained when the car is not on.

Background: I had the car there for a change out of A/C components (compressor/dryer/etc. $2,800) in August and the problem first occurred but didn't recur after taking it in then. My thought is that the battery is being drained constantly from somewhere (a short maybe?). The car killed a 1 year-old battery shortly thereafter. My shop replaced the battery; problem remains.

My shop is giving me a bit of the cold shoulder saying that they don’t think it could be anything they did when the A/C was worked on (even though the fuse box, gas tank, etc. has to be removed to get to the A/C components); said he thought it was the key ignition switch, which they said they replaced but that didn’t affect the problem. The car was there for 8 workdays and that is all they could tell me. I am not even sure the ignition switch was replaced. It seems like it could be the ignition. I have connected a multimeter to the battery and it has 14 volts. One of the shop's theories was that the battery was being drained by the radio (aftermarket in dash CD with amp in trunk, installed before my ownership 5+ years ago). I took out the fuse for the radio, no real change in voltmeter reading. No change either when fuse for gauges taken out. Then on the PCA forum, I posted this question and evidently I should have been checking amps changes, not voltage changes.

My last resort is to either take it to another shop or the dealer to get a second opinion.

Any ideas?