Engine Cool fan and AC problems

[JussRJ]

I have a 2008 mustang and I’m having problems with my AC and fan.. My car runs hot after about 30min driving and I believe it’s due to the fan not kicking on. So I tested relays for the AC and high and low fan all is getting power. The fan sometimes comes on and and goes back off the same with compressor the compressor comes on and goes off within 2/3 second intervals. I noticed Also the top radiator hose doesn’t have pressure when the car overheats. Don’t know if this has anything to do with the problem seems electrical of some sort but the horn recently stopped working. It gets power when I run a connection straight from the battery but it doesn’t sound when I press the horn pad and the alarm chirp doesn’t work. I could press the panic button on remote and the lights flash but don’t sound. I replaced the clock spring and horn spring already problem still occurred. One day while raining the horn did work but only when the car sat still and once I turned the steering wheel it would stop again. I love my mustang but this is a headache.

 

[Bullitt95]

Sounds like you have two separate unrelated problems.

1. Check the fan relay terminals and the terminals inside the underhood fusebox to see if they're melted. If so, there's a short in the fan circuit and the likely source is a bad fan resistor.

2. Check the front passenger floor and the smart junction box for water contamination. The horn problem could be due to a blown fuse, corroded terminals inside the SJB, or a blown horn relay.