Horn Relay, Ballast Resistor are HOT

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jawacz1

jawacz1

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1974 Duster. With Key on the Horn Relay and Ballast resistor get Very Hot. What could be causing this?
 
ballast does get hot, that's why its ceramic and changes resistance with heat, the hotter it gets the more resistance it creates to reduce the voltage to the coil. A Horn relay is simply an electromagnetic pole tied to a microswitch. the coil of the elctromagnet energizes when you hit the horn and the new magnetised pole pulls the contacts closed to operate the horn. Its a way to allow a very small capacity switch (horn button) to trip a large amp draw device and not melt. If the relay is hot to the touch, you may have a grounded coil inside the relay. They are inexpensive to replace, but you could test with a multimeter the various contacts. one is going the be ground. This one has a buzzer for the seatbelts IIRc. Violet is power in...?
relay.jpg
 
pishta said:
ballast does get hot, that's why its ceramic and changes resistance with heat, the hotter it gets the more resistance it creates to reduce the voltage to the coil. A Horn relay is simply an electromagnetic pole tied to a microswitch. the coil of the elctromagnet energizes when you hit the horn and the new magnetised pole pulls the contacts closed to operate the horn. Its a way to allow a very small capacity switch (horn button) to trip a large amp draw device and not melt. If the relay is hot to the touch, you may have a grounded coil inside the relay. They are inexpensive to replace, but you could test with a multimeter the various contacts. one is going the be ground. This one has a buzzer for the seatbelts IIRc. Violet is power in...?
View attachment 1715362846
Click to expand...
Thanks for the info on the ballast. I just ordered a new relay so I'll see if the new one is OK. Thanks again!
 
Does the horn work? If the relay was shorted the horn would not work or it would be honking all the time.
 
Dana67Dart said:
Stock wiring?
Click to expand...
I thought so until I started looking closer this morning.
Dana67Dart said:
Stock wiring?
Click to expand...
I dont think so ... there is a green wire spliced to the positive battery terminal (it is wrapped in electrical tape and comes out the other end red ) then it attaches to the solenoid. That doesn't seem to be a mopar factory practice! I'm going to get my Hayne's manual out and check out the wiring diagrams. Thanks!
 
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