i bought a new horn cuz he original was getting worn out. so i disconnected the battery pulled the old horn, installed the new horn, connected the battery back and all i get is a click coming from inside the cab under the glove box when i hit the horn button. well figured it was a bad horn by chance i disconnected the battery pulled the new horn, put the old one back on. still the same click when you hit the horn. then i start to think maybe its a blown fuse, locate where the fuse is, but its also for the cigarette lighter and a few other interior things, they all work though. any thoughts?

 

If you posted the year of your truck, it might help.
They aren't all wired the same.
The problem sounds like the horn relay but it's not located behind the glove box on my '96. No telling where it is on your truck without more information

 

"horn broke watch for finger" check your power and ground. very easy circuit to check. check the owners manual for fuses

 

its a 91

 

relay gets 60ohms on one path and i think it was 0 or ol on the other? does that sound about right? and im getting 12 volts at the relay connector but not at the horn

 

swap the relays to make sure it isnt the relay. check any fuses in circuit. and if all that checks out start chasing down wires. check the connector pins to make sure they arnt bent or pulled out. maby just dirty.

 

checked fuse its good. gonna run to autozone tomorrow and get relay. thanks

 

Check the relay before you replace.
With the horn button pressed, you should have12v at the "control voltage in" pin (pin #86 if they are numbered conventionally.) With the horn button not pressed you should read 0 ohms or very close to it at the "control ground" (pin #85.) Since your relay is clicking when actuated, you are probably going to see those readings.

On the power side of the relay you should also see 0 ohms at the "power ground" (pin #30.) If you do not see 0 or a very low number, clean the ground and re-test. A dirty or corroded ground is a very likely culprit. Finally, with the horn button pressed you should see 12v at the "power out" (pin #87.) If you have 12v there, the problem is not the relay, it's in the wire between the relay and the horn.