Thanks for the replies.

I ended up using a multimeter and tapping right into the pins on the temperature regulator harness. If you follow the instructions on the CD under Climate Control troubleshooting, it indicates the approriate pins to use for each test. It also gives a wiring diagram for confirmation. The results of the various tests (for in-car temp sensor, heat exchanger temp sensor, blower, etc.) fell at or near the cd's given ranges, hence the testing method was working.

I am glad to learn this method since the adapter/tester was quoted at $254 by Phil. Sorry Phil, I've bought a lot of stuff from you, but not this one.

Happy St. Paddy's Day

Rich Mayer
82 500 SL