My daughter's sunfire 2003 model....suddenly the horn , and heater doesn't work

Check the relay, if you have one, it could be the horn switch too

HI. The first check point will be the fuse. make sure that the fuse filament isn't severed. This is common. If the fuse is in good condition, move onto the wiring and horn device. There may be a disconnection at the horn connection point. You can also test the connection wires for shorts, as well.

More than likely the actual horn may need to be replaced if the wiring and fuse prove to be in good condition. A basic multimeter can be used for the wire test, if you have one.

NOTE: In rare cases, the horn switch in the steering wheel could be the culprit, although, highly unlikely in most cases.

The problem may be not due to the relay but the button on the horn pad sticking. If you try tapping on the horn button and can get the horn to turn off, you may need to remove it and determine if there's any deterioration of springs or foam the hold the contacts away from each other. Depending on the specifics of the button you may be able to restore function.

Under hood in a plastic box, should have digrame to show you witch one is horn relay. good luck to ya.

I would take the wires off of the horn, clean the terminals and replace. you mighr not be making a good connection.

try the fuse box

just renew the horn and make sure it has a good earth

does blower work,,,try & find heater hoses.see is both are hot,,if not heater core

check connections ensure plug isnt corroded the horn can short out and not work may need a replacement

get one of those bumper stickers that says"horn broke watch for finger"!!! msot horns usually get water in them you need to check and see if your getting poer at horn.use a test light at horn and have someone push horn button. also can try tapping horn with a hammer whil;e someone pushes horn pad. if no power then check fuses and relay