2005 PT Cruiser

stroh

The horn, fuel gauge and cruise control all went out at the same time. The fuel gauge arrow will go up to full when you sr=tart the engine but then drops down to empty. We checked the horn at the engine and it worked but not using the button on the steering wheel. Has anyone else have this happen?

thecardoc3

Diagnostics would start with a professional level scan tool. The cruise control switches are inputs to the engine control module. Operating them while watching scan data would show if the controller can see them or not. The horn itself is a pretty simple circuit, the horn pad grounds the control side of the relay which is in the underhood fuse block. The fuel gage operates by the engine control module sending fuel level information across the databus to the instrument cluster. That could be a problem with the sending unit or it's wiring and it could easily be a problem with the gage or the instrument cluster. Again the professional evel scan tool would let a technician see if the engine controller is getting the required (and correct) information from the fuel level sending unit and then he/she could look at the instrument cluster data and see if it is getting the right information sent to it.