[Majik]

I replaced my alternator yesterday and my speedometer stopped working. I checked the fuse and it was blown. I tried replacing it twice and it would blow immediately. I tried a slightly higher amp fuse and it also blew out instantly. What could be causing this?

 

[Boston-Bull]

Sounds like a short somewhere

 

[Majik]

Right...but where to start looking is the ultimate question...

 

[master486]

Since you had problems with the alternator, I would look at the wires going to the voltage regulator and check for melted wires.

 

[Superduty]

When the fuse blowes dose the tach still work. Is the fuse a 10amp or 5amp.

 

[guitar maestro]

there is one wire on the driver-side of the main engine harness that is a "turn on" wire for the alternator (hot with key-on) as well as the wires that go to the voltage regulator on the back of the alt that need to be checked

 

[Majik]

Upon physical inspection, both of the above mentioned wires seem to be fine.

 

[guitar maestro]

you're using physical inspection techniques for diagnosing an electrical problem?? i would tend to think electrical inspection techniques would be more appropriate

 

[texashurst]

the speedo fuse might have anything to do with the alt swap. Check the speedo wire at the trans and see if it landed on your exhaust. That happened to me in a blazer once shut down the whole ecm. Thats where I would start.