B122 - Twilight Delay & Panel Dimming

Chart:

Schematic:

DESCRIPTION
Since both potentiometers use the same power and ground, chances are that the problem is in the power or ground circuits when both codes are stored.

TEST DESCRIPTION
The numbers below refer to circled numbers on the diagnostic chart:
1. Body Control Module (BCM) data value ED43 displays a twilight delay value. The normal range is between 6 and 94%.
2. Check to see if the open or grounded circuit reading is due to the circuit or the switch assembly. If voltage can be read across CKTS. 705 and 736 after disconnecting the switch assembly, the BCM and wiring are OK.
3. Check for 5 volt reference at the switch. If 5 volts are present CKT 736 is open. If CKT 736 is open, the open will be between term. BC1O on left switch assembly and cavity C3 on dash Instrument Panel (IP) transition connector.
4. If CKT 705 is suspected of being grounded, remove the Heating Ventilation and Air Conditioning (HVAC) programmer and BCM connectors prior to making a ground check.
5. If there is no ground in CKT 705 replace HVAC programmer or BCM.

NOTE ON INTERMITTENTS
If an intermittent codes B120 & B122 are being set, manipulate the related wiring while observing either BCM data VALUE BD42 and/or BD43. If the failure is induced, the reading will jump from its normal value to a reading outside of its range, (see specific charts for range).