Pinpoint Tests

PINPOINT TEST A: HORN SYSTEM ALWAYS ON

A1 CHECK HORN SWITCH CIRCUIT FOR SHORT 

• Remove horn relay and bracket as outlined.

• Disconnect positive battery cable and wait one minute.

• Using ohmmeter connected to a known good ground, connect other lead to Pin 3 Circuit 6 (Y/LG) at relay connector.

• Is resistance 5 ohms or less?

GO to A2.

No
REPLACE shorted horn relay and bracket . RESTORE vehicle. RETEST system.

 

A2 CHECK HORN SWITCH FOR SHORT

• Disconnect driver side air bag module as outlined.

• Disconnect horn blow switches as outlined.

• Ohmmeter still connected to relay connector and ground read resistance.

• Is resistance 5 ohms or less?

Yes
GO to A3.

No
REPLACE shorted horn blow switch . RESTORE vehicle. RETEST system.

 

A3 CHECK FOR SHORTED AIR BAG SLIDING CONTACT

• Disconnect ohmmeter from relay connector.

• Carefully check resistance of each contact air bag sliding contact.

• Is resistance 5 ohms or less?

Yes
REPLACE shorted air bag sliding contact. RESTORE vehicle as outlined. RETEST system.

No
SERVICE short to ground Circuit 6 (Y/LG). RESTORE vehicle as outlined. RETEST system.

  

PINPOINT TEST B: HORN SYSTEM INOPERATIVE

 

B1 CHECK HORN OPERATION 

• Disconnect both horns as outlined.

• Connect one end of a jumper wire to battery positive.

• Touch other end to connector at each horn .

• Did each horn sound?

Yes
GO to B2.

No
REPLACE horn or horns that did not sound. RESTORE vehicle. RETEST system.

 

B2 CHECK HORN CIRCUITRY

• Using a test lamp, connect lead to a known good ground.

• Connect other end to horn harness connector. Position test lamp in visible position.

• Actuate horn blow switch .

• Did test lamp illuminate?

Yes
System OK. RESTORE vehicle. RETEST system.

No
GO to B3.

 

B3 CHECK HORN FEED AT RELAY

• Remove horn relay and bracket as outlined.

• Connect test lamp to known good ground.

• Connect test lamp probe to Pin 2 Circuit 1 (DB) at relay.

• Actuate horn blow switch .

• Did test lamp illuminate?

Yes
GO to B4.

No
GO to B5.

 

B4 CHECK HORN CIRCUIT CONTINUITY

• Using ohmmeter, connect one lead to horn harness connector. Connect other lead to Pin 2 Circuit 1 (DB) at relay connector. Read resistance.

• Is resistance 5 ohms or less?

Yes
GO to B5.

No
SERVICE open in Circuit 1 (DB). RESTORE vehicle. RETEST system.

 

B5 CHECK HORN SYSTEM SUPPLY

• Using test lamp connected to a known good ground, connect test lamp probe Pin 1 Circuit 40 (LB/W) at relay connector.

• Did test lamp illuminate?

Yes
GO to B8.

No
GO to B6.

 

B6 CHECK SUPPLY CIRCUIT

• With test lamp, check fuse 16 (20A) at instrument panel .

• Is fuse OK?

Yes
SERVICE open in Circuit 40 (LB/W). RESTORE vehicle. RETEST system.

No
GO to B7.

 

B7 CHECK FOR SUPPLY SHORT TO GROUND

• Using ohmmeter, check continuity from Pin 1 Circuit 40 (LB/W) at relay connector to a known good ground.

• Is resistance 5 ohms or less?

Yes
SERVICE short to ground Circuit 40 (LB/W). RESTORE vehicle. RETEST system.

No
GO to B8.

 

B8 CHECK HORN RELAY

• Reconnect horn relay and bracket .

• Using test lamp connected to a known good ground, connect probe of test lamp to Pin 3 Circuit 6 (Y/LG).

• Did test lamp illuminate?

Yes
GO to B9.

No
REPLACE horn relay and bracket . RESTORE vehicle. RETEST system.

 

B9 CHECK HORN SWITCH FEED FOR OPEN

• Disconnect battery positive cable as outlined. Wait one minute.

• Disconnect driver side air bag module .

• With test lamp connected to known good ground, check Circuit 6 (Y/LG) at horn switch connector.

• Did test lamp illuminate?

Yes
REPLACE horn switch. RESTORE vehicle. RETEST system.

No
SERVICE open in Circuit 6 (Y/LG). RESTORE vehicle. RETEST system.

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