headlight issue 2006 pt cruiser

Low beam bulb(s) work(s) on the right side but not the left.
Seems to be a commonly asked question in cyberspace but with little to no response. Examples....
http://www.2carpros.com/questions/chrysler-pt-cruiser-2006-chrysler-pt-cruiser-left-headlight
http://www.fixya.com/cars/t6049638-2006_chrysler_pt_cruiser

Fairly confident the socket/wire harness to the bulb connection is good.
Voltage at socket on right side is 12.3, on the left nonworking side 11.4 or so.

A couple relevant cyberspace responses to others' inquiries, which I can't seem to find again, mention a bad module or a bad switch or compromised wire in steering column. Which, if any, are best bets to try first??

if you have 11.4 volts on the violet wire into the headlamp; check the black ground wire out of the headlamp. the hi and low beam share a ground at the frame, but from the wiring diagram, run separate ground wires out of the headlamp unit and splice together later.

Supply a ground for the low beam circuit and see if the light works.

Thanks -- I'll look at that tonight.

Update/results
Local garage diagnosed no power to left low beam headlight the fault of the TIPM. They wanted $700+ to order/install a tipm replacement.

Thanks to an internet 'tipm' search and the info in the quote below, ended up taking it to dealer and they reset the TIPM for <$200.

"It is common in the 2006 models which was the year they did away with the interior fuse box and installed a T.I.P.M that when one thing goes wrong it is usually accompanied with a few other problems. The TIPM is a totally integrated power module that is under the hood that the few fuses you do have plug into which connects to two multifunction switches/ control modules on the right and left sides off your column which control lights wipers etc. problems usually occur when aftermarket items are added to the vehical and are wired incorrectly items such as a towing harness, alarm system, or stereo system. These items when not properly installed with an in-line fuse can 'overload' the TIPM or the modules in the column this can be fixed very quickly by the dealer and the dealer only by a process called flashing. They just plug in a tool and reprogram the TIPM and modules it should cost you no more than 300 dollars and make sure they rewire what overloaded the TIPM in the first place." http://www.cargurus.com/Cars/Discussion-t27237_ds476615