OK. Because I hate it when there is no resolution to a thread, I thought I'd offer what appears to be the end to my heat problem. The indy shop had my car for 3 days, during which time they were torn between replacing the duovalve and HSCP, and replacing the Climate Control Unit. They ended up leaving in the original CCU, and doing the duovalve et al. I picked it up on Friday evening and I had heat. Saturday AM I checked it again and I had no heat. No heat again on Sunday. Took it back Monday afternoon and on the way I had heat again. Very strange. They replaced the climate control unit, and now I seem to have heat any time I want it. (Of course, it's only been 2 days so I've still got my fingers crossed.)

Total bill to get heat in August: $1,600.00. Could have ordered the parts here for about $900.00 and done it myself, but the car might still be in pieces.

I hope of this helps someone out there somehow.

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1993 500 SEL 121,000
2003 Toyota 4Runner 4X4 Limited (Sweet!)
1995 Ford Bronco 351 Windsor 135K miles (Hunting truck)

Past Vehicles
1999 Landrover Discovery II 46,000 (Sold)
1998 Lexus ES300 (Sold to get my Benz)
1973 Chevy Nova SS (drove it till the body fell apart in '87)
1971 Chevy Camaro (wrecked in high school)