In the morning or when the car is cold <32 degrees and I start it it makes a horrid horn noise until it warms up! I lifted the hood to see where its coming from and it seems to be coming from the air pump side or back by the fire wall! Maybe like a valve or something.. Anyone else have this happen?? And what is a remedy?? Thanks

 

could be that the pump is going and with the temperature as low as you state it is most likely condensation that is makin the pump have that noise (inside frozen)..one way to find out is temporalily take the belt off (JUST FOR THE TEST)..to see if the noise disappears..if it doesn't that rules the air pump out as the noise maker ..just guessin

 

Might also be the coolant sensor. Check your coolant leve to see if its low. Also check your belts if there glazed up a bit.

 

yup sounds like the low coolant or oil sensor. not the horn

 

The sound isnt one of the low level sensors in the cab. Its under the hood from around the left rear part of the engine around all the vac lines/valves and stuff. Sounds "like" a horn . Not a buzzer!! and its only when its cold, until its warmed up.