How critical is ignition switch fuse match?

[Wolfy]

The day I posted "no problems" at +/- 3000 miles, we ended up needing a $200 tow-and-taxi trip that left the rig at a dealer and us at home.



The problem - after starting/running fine all day, the truck ('07. 5, 3500, 6. 7) refused to even try to start. All dash "check lights" illuminated, but no response to start position of either of two keys. No click, no sound, no nothin'. No amount of lever/wheel wiggling, park/neutral shifting, or owner's manual reading helped at all.



Dealer service found blown fuse (#22 - 2 amp). Could not find any reason, . . but replaced ignition switch , and problem seems to be solved.



The question: When I looked to verify the fuse size, I found that the fuse was replaced with a 5 amp size, rather than the specified 2 amp.



I. e. , this fuse will permit 2 and a half times the current through the circuit, compared with what Dodge intended.



Anyone have thoughts or knowledge regarding undesirable consequences?



Thanks for any responses,

 

[RGrizzle]

The day I posted "no problems" at +/- 3000 miles, we ended up needing a $200 tow-and-taxi trip that left the rig at a dealer and us at home.



The problem - after starting/running fine all day, the truck ('07. 5, 3500, 6. 7) refused to even try to start. All dash "check lights" illuminated, but no response to start position of either of two keys. No click, no sound, no nothin'. No amount of lever/wheel wiggling, park/neutral shifting, or owner's manual reading helped at all.



Dealer service found blown fuse (#22 - 2 amp). Could not find any reason, . . but replaced ignition switch , and problem seems to be solved.



The question: When I looked to verify the fuse size, I found that the fuse was replaced with a 5 amp size, rather than the specified 2 amp.



I. e. , this fuse will permit 2 and a half times the current through the circuit, compared with what Dodge intended.



Anyone have thoughts or knowledge regarding undesirable consequences?



Thanks for any responses,

i am an electrician and see people that try to solve a short by using too big of fuse or breaker every day . that is one reason for electrical fires . the purpose of an overcurrent device such as a fuse or breaker is to 1. protect the wire 2. protect the device it is controlling . a wire is made to accept only a certain amount of current . if that amount of current is exceeded , the wire burns . also , some devices can only handle a certain amount of current or it melts or burns . i don't know what size wire your fuse is protecting , but it would have to be very small for a 5 amp fuse to overload it . on the other hand , the device (whatever it may be) that is being protected may not be supposed to have over a 2 amp fuse or it could melt . there was some reason dodge recomended the 2 amp fuse so that's defineately what i would put in it . i had a mechanic work on the a/c on a work truck of mine and he called and said he had it working so, we went and picked it up . about an hour later we began smelling smoke . all he had done was put a bigger fuse in for the a/c and it melted the wires because the short was still there and the fuse he put in was now too big to protect the wire like it was supposed to . ---------------------- by the way , as long as there are no problems or shorts , there shouldn't be too much current flowing but the purpose of the over current device is to blow before the short or overload has a chance to melt the wire or device .

 

[Dishman Dodge]

Wolfy,

In case you didn't get the message yet, I verified this w/ our lead tech, and he is in total agreeance w/ RGrizzle, I would replace the fuse w/ a 2 amp fuse, and probably let the service manager who you will be talking w/ know about this.

Talk to you soon,

-Josh

 

[Wolfy]

Wolfy,

... I verified this w/ our lead tech, and he is in total agreement w/ RGrizzle, I would replace the fuse w/ a 2 amp fuse, and probably let the service manager who you will be talking w/ know about this.

Talk to you soon,

-Josh

Thanks RGrizzle and Josh! ;-)



Sound advice, I think.



I told the service dept that I wanted the 2 A. fuse replaced with the same, or a note to the effect that a 5 A. had been substituted initialed on the invoice by the service manager.



Not surprisingly they are replacing the 2A. (The truck is still in the shop for a poor dash fit issue. )



Seems to me that if the replacement of the ignition switch fixed the problem, then there is no need to change the fuse spec. If the switch was NOT the problem, then maybe the 2A. should be there to protect against whatever the problem really was, ... since some sort of overcurrent situation may raise its ugly head again.



Spare fuses in the tool kit, and away we go!