Component Tests and General Diagnostics
HORNS DO NOT SOUND1. Remove Horn Relay and check for battery voltage at relay connector terminals 30 and 85.
^ If battery voltage is present at both terminals, go to step 2.
^ If battery voltage is not present at terminal(s), check RED (1142) wiring and Right Front Underhood Relay Center "HORN" Fuse for an open.
2. With Horn Switch depressed, measure voltage from relay connector terminal 85 to terminal 86.
^ If battery voltage is present, go to step 3.
^ If battery voltage is not present, check BLK (28) wiring for an open; check in-line Connector C202 for proper terminal contact; check Spring Loaded Contact, Slip Ring, and Horn Switch for an open.
3. Connect a fused jumper from relay connector terminal 30 to terminal 87.
^ If horns do not sound, go to step 4.
^ If horns sound, replace Horn Relay.
4. Disconnect suspect horn connector. Connect a fused jumper from suspect horn terminal B (DK ORN) to positive battery terminal.
^ If horn sounds, check wiring to Horn Relay for an open or short to ground
^ If horn does not sound, check that G103 is clean and tight, and check BLK (1350) wiring for an open, if OK, replace suspect horn.
HORN TONE QUALITY POOR
^ Refer to System Diagnosis.
HORNS SOUND AT ALL TIMES
If horns sound at all times, separate in-line Connector C202.
^ If horns stop check Horn Switch and its wiring for a short to ground.
^ If horns continue to sound with in-line Connector C202 separated, check BLK (28) wiring for a short to ground and DK ORN (29) wiring for a short to battery; if OK, replace Horn Relay.
^ For Buick with Theft Deterrent (UA6) only, remove I/P 1 Fuse from Rear Fuse Block to disable Retained Accessory Power, if horn stops, refer to Accessory Delay Module. Accessory Delay Module