Horns Inoperative - Hummer H1 Service Manual

12-62 Electrical System
Step
1 Locate the horn assemblies under the hood.
Disconnect the harness from the horn assemblies.
With a DVOM check the black wires (CKT 58) for
resistance to ground. Do both wires meet with
specifications?
2 With a DVOM back probe the white wires on the
horn assemblies and check for voltage when the
horn button is pushed. Is the specified voltage
present?
3 Remove the horn relay from the exterior fuse box.
With a DVOM check resistance between the relay
cavity 1F and the white wire (CKT 6) on the horn
assembly. Does the resistance meet the
specifications?
4 With a DVOM check for voltage in cavities 3E
and 1E of the exterior fuse box. Is the specified
voltage present?
5 With a DVOM check the resistance to ground on
cavity 3F, of the exterior fuse box, when the horn
switch is pressed. Does the resistance meet the
specifications?
6 Gain access to connector C39. With a DVOM
back probe cavity C on connector 39. Activate the
horn switch and watch the resistance on the meter.
Does the resistance meet the specifications?
4-1-00
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Horns Inoperative

Action Value Yes
<.2 Ω
Go to step 2.
12v Replace the horn
assemblies.
<.2 Ω
Go to step 4.
12v Go to step 5.
<.2 Ω
Replace the
horn relay.
<.2 Ω
Repair the open
or bad connection
on CKT 1
between the horn
switch and the
horn relay.
®
No
Repair the open
or bad connection
on CKT 58
between the horn
assemblies and
G2.
Go to step 3.
Repair the open
or bad connection
in CKT 6
between the horn
relay and the
horn assembly.
Repair the open
or bad connection
in CKT 7
between the horn
relay and the
exterior fuse box.
Go to step 6.
Replace the turn
signal assembly.