[am1955]

Have a 1988 Deville 4.5L (I believe the one with trasversal V8)

Have issues with my 25A Climate fuse blowing (random) early in the morning shortly after the car is firedup (approx 3 min idle to warm water for heat).

With temperature settings at 90deg. when the "Auto" button on the control is pushed, with in 30 seconds the fuse will blow. This is not my car (daughter) and was told that a strage screaching soound ocurrs just before teh fuse blows. When I tested it and blown 3 fuses, I did not hear any strange noises, but the fuse definately blows. The same test scenario with "Econ", never blows the fuse.

The only abnormal thing I found is a "patented relay" on relay panel located on the passeger side, located on the top right side of this board. this relay was extrimely hot (could not touch it for more then 1/2 sec). I have removed this pending getting a replacement.

Any help/suggestions are greatly appreciated.

Adriano:suspense:

 

[noahsdad]

Using the "Auto" function engages the AC compressor, even if heat is required to meet the desired cabin temperature. The "Econ" setting bypasses the compressor and simply blows air over the heater core. The screech you're hearing could be the compressor bearings or the serpentine belt trying to engage a very tight compressor pulley.

If the compressor is going bad, it's ain't cheap. My '87 SDV just cost $970 for a new GM compressor and conversion to R134. You can buy some time by purchasing a shorter belt and bypassing the compressor, then using only the "Econ" setting to provide heat or fresh air. I think there are a couple of posts in the 4.1/4.5/4.9 engine section about how to do this.

Good luck! Post how it turns out.