You bought a vehicle with a lot of unnecessary, complicated, unreliable, and expensive computers. Expect a comparable repair bill. This is partly why no one wants to buy new cars. It really frustrates me, and it's why I still drive a 1988 Grand Caravan. It uses a ten-dollar relay that rarely gives a problem. Be thankful you don't have a Ford. Two computers involved in blowing the horn! Typical cost of their inoperative horn is around $800.00.
As for your horn, it is likely being turned on by the Body computer or the Remote Keyless Entry computer. Is it possible someone nearby is using a key fob set to the same frequency as yours? If so, this problem would likely occur in the same place, such as work or home, not on a shopping trip.
Under normal conditions, your tail lights probably flash when the alarm sounds? If they do not flash when this intermittent problem occurs, I'd suspect a body computer problem. If they do flash when the horn honks unexpectedly, I'd troubleshoot a security system issue. Is there a possibility this is still under warranty? If it is, as long as the problem is documented as occurring in the warranty period, they will usually still take care of it if it's out of warranty when they finally find the cause.
Sunday, March 29th, 2009 AT 11:30 PM