Horn does not work when engine compartment is hot!

[Mike Pyne]

The horn always work when the vehicle is first started regardless if the outside temp is +100 degrees or not. Horn also works fine in 100+ degree heat while driving the vehicle. However once we stop for a while (15 minutes) and the engine compartment heats up past 110 degrees (Milwaukee infrared gun reading) the horn and only the horn stops working. Everything else works fine, lights, trailer, trailer brake, etc, all good.

 

We replaced both Hi & Lo horns, cleaned & lubed the horn connectors and the 5 large connectors under the fuse/relay block. We read +12.8vdc at the horn.

I suspect that the non-replaceable horn relay imbedded on the fuse/relay pcb board may be failing when hot. Or perhaps it is a body control module issue.

 

Any help would be appreciated.

Best regards,

Mike

[Mike Pyne]

Which module is bad or could be effected by high engine compartment temps, Fuse/Relay PCB, BCM, ECM ?

When we use a leaf blower and cool down the engine compartment below 90F, the horn works fine again! 

 

OBDLINK MX+ DTC:

Currently there are (0) none!

 

OBDLINK MX+ DTC Historical Data: (note: the license plate lights and all lights inside/outside the vehicle work!)

B3883-01 License Plate Lamp Circuit Short to Battery

B3883-04 License Plate Lamp Circuit Open

 

[KevinAhmad]

Hello Mike,

 

what was the issue?   My 2015 Silverado standard cab is suffering from same issue.  I too suspect integrated relay.