here are the codes i found on some other thread in this very forum.
they have a url for a pontiac but it's the same thing.
http://www.bonnevilleclub.com/techinfo/?article=45
here :
00 - No codes
10 or 110 - Ambient Temp Sensor circuit open or shorted.
13 or 113 - In-Vehicle Temp Sensor circuit open or shorted.
15 or 115 - LH Solar Sensor circuit open or shorted.
35 or 135 - Data Line failure - HVAC Control Assembly
38 or 138 - Data Line failure - PCM
40 or 140 - Driver Air Mix Motor circuit open or shorted, or not calibrated
48 or 148 - Long Term Freon Loss
52 or 152 - Keep Alive Memory lost; sets with battery disconnected
66 or 166 - Low Freon
A number 1 prefix indicates a history trouble code
4. Press OFF twice once codes are displayed to end diagnostic mode, OR to clear trouble codes, press FAN DOWN three times (make sure 03 is displayed).
Once 03 is displayed, press FAN UP to clear trouble codes. Then repeatedly press OFF to end diagnostic mode.
your 188 could more like a 138.. no?
there must be some more of them since yours aint there...
maybe someone will post the others?
Deadring