Technical 7.5 amp fuse F16 to ECU intermittently blowing

[Irlanski]

Hi All,
My 2005 Fiat Punto 1.2 Classe is continually blowing the 7.5 amp F16 fuse in the engine compartment. Then the dashboard shows the orange immobilizer padlock light leaving it possible to crank the engine not start - nor will you hear the normal operation of the fuel pump for the usual couple of seconds after you turn the ignition on. I don't think the dashboard gauges operate either when this fuse is blown.

I think this fuse feeds the ECU and possibly a few other items. When it blows the car just dies on the side of the road. If I replace the fuse it sometimes blows immediately on turning on the ignition or it may not blow again for days, so frustrating, it's like an intermittent short somewhere.

I'm struggling a little to get the correct wiring diagram but it would be great if someone could put a finger on the normal cause of this problem. I have tried a 10amp fuse but no better.

Any help much appreciated.

Irlanski

 

[jackwhoo]

Try and find out every electrical component the fuse in question protects.

If you can turn on any of the components by switch in car , turn them on one at a time checking if fuse blows. That way you may identify if you have faulty component.


The owners hand book may identify what the fuse protects.

Please don't fit a higher value fuse , you could cause a fire in your car with you inside.

 

[Fialfa]

Long shot but did someone play with wiring on ignition to turn stereo off with key ? Have a look at wiring around the ignition , particularly any wire that looks added , back of Stereo and clips all tight on Ecu

 

[jackwhoo]

Starting at engine ecu working back look for any areas where loom may have rubbed against any metal causing a short circuit.

I like the previous suggestion of checking ingnition switch very much- smart thinking.

 

[Fialfa]

As jackwhoo says it’s most likely worn
Wiring / let car idle and go and move wiring from ecu / behind headlights etc and see does it do anything / I’d say secondly check for dodgy stereo wiring to ignition or elsewhere under dash also move the ignition wiring when running as keys may be moving loose wires behind the ignition on the move , then possibly it’s loose ecu clips or maybe as a last resort look at the fuel pump itself if that’s dodgy it could cut the fuel and cause the same problems