Horn only works when the ignition is off.

[Green96]

1996 gmc 1500 horn only works when ignition is off. Turn the key on it’s dead. I replaced the multifunction switch still not working. Thanks

 

[GoToGuy]

Why did you replace the multi switch?

 

[Green96]

It grounds though the switch and the pin contact is on the switch that hits the horn contact that is on the steering shaft. I was hoping it was something with that switch because it not only has the black ground thin wire number 11 on the harness connector to the main harness and the pin connector the hits the horn contact on the steering shaft. Works fine in the off position as soon as it is in the on/run position nothing. Thanks for reading my post maybe someone else had this problem. Thanks.

 

[east302]

Have you backprobed A11 at C266?

I couldn’t find a pinout to see what else runs through it (headlights?), but do you get voltage at connector C101 with it running and the horn pressed?

Does it work with ignition in the accessory position? How about with headlights (or DRL) on or off?

Diagrams are from the 96 manual.

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[Green96]

Thanks for the great information and help, I will try all of this and report back. Thanks.