Fuse 1 BLOWS!
Posted: Wed Aug 29, 2007 9:20 am
Hello to everyone, I'm a long time Beretta owner and a new member here.  After years of piddling with this car (My wife bought it new in 1988) it may finally have me beat.  It is a 1987 Beretta 2.8 with the auto transmission and has been an extremely reliable car over the years.  At 251,000+ miles, neither the engine nor trany has ever been into and it has been a daily driver for all this time!  It burns no oil and until last Thursday still ran like a top (though the front suspension is about shot).  I will probably have to replace it as a daily driver but I would still like to keep it as a back up.
What is happening now is that the #1 fuse in the fuse box by the driver's side door is blowing the instant the ignition is turned on.  I was driving Thursday and had gone about ten miles.  I turned left and the car quit like it had the ignition switch cut off.  No stumble, hesitation or anything, just dead.  It wouldn't restart and I could no longer hear the fuel pump run up.
I finally discovered the blown #1 fuse and have been trying to figure out what is blowing it.  I have tested it at the fuse box with the fuse out using an ohm/voltmeter and the right side of the circut puts out twelve volts just fine when the ignition is turned on.  But with the ignition off both sides read as grounded on the continutity test.  I have also disconnected the direct ignition module (the smaller connector with two or three wires one of which is pink) and tried a new fuse which also propmplty blew!  So I am thinking the DIS module is ok.
As near as I can tell from the wiring diagrams in Haynes and the Allen Institute GM PFI manuals, the ECM, fuel injectors and intrument cluster also run off this circut (the diagrams list the wire as pink and black but on my it appears to be pink and white, at least at the fuse block).  All I can think to do is to disconnect each one and retest the circut with a new fuse and see when it doesn't blow.  If it still blows with all disconnected I guess I start looking for a bad or bare wire ground fault?
Does anyone have any other suggestions?  Could it be the ignition switch?  It is still original as well but since it does put out 12v ok when switched on I thought it was probably ok.
Sorry to be so long winded but this one really has me chasing my tail!  Thanks for any help!  And thanks to Jeff P since his post on this site help put me onto the fuse 1 issue.
Hoping against hope
Reb
What is happening now is that the #1 fuse in the fuse box by the driver's side door is blowing the instant the ignition is turned on.  I was driving Thursday and had gone about ten miles.  I turned left and the car quit like it had the ignition switch cut off.  No stumble, hesitation or anything, just dead.  It wouldn't restart and I could no longer hear the fuel pump run up.
I finally discovered the blown #1 fuse and have been trying to figure out what is blowing it.  I have tested it at the fuse box with the fuse out using an ohm/voltmeter and the right side of the circut puts out twelve volts just fine when the ignition is turned on.  But with the ignition off both sides read as grounded on the continutity test.  I have also disconnected the direct ignition module (the smaller connector with two or three wires one of which is pink) and tried a new fuse which also propmplty blew!  So I am thinking the DIS module is ok.
As near as I can tell from the wiring diagrams in Haynes and the Allen Institute GM PFI manuals, the ECM, fuel injectors and intrument cluster also run off this circut (the diagrams list the wire as pink and black but on my it appears to be pink and white, at least at the fuse block).  All I can think to do is to disconnect each one and retest the circut with a new fuse and see when it doesn't blow.  If it still blows with all disconnected I guess I start looking for a bad or bare wire ground fault?
Does anyone have any other suggestions?  Could it be the ignition switch?  It is still original as well but since it does put out 12v ok when switched on I thought it was probably ok.
Sorry to be so long winded but this one really has me chasing my tail!  Thanks for any help!  And thanks to Jeff P since his post on this site help put me onto the fuse 1 issue.
Hoping against hope
Reb