Blown fuses

[chazpo64]

My 99 Tahoe keeps blowing the hazard, break light and turn signal fuses all at the same time. I've checked the main illumination fuse under the hood and it's ok.

 

[lesterl]

Check for shorts in MFC switch, wiring to lights at all 3 corners, sockets, and brake light switch....

 

[remauto1187]

A short (circuit) in the brake light switch would cause the brake lights to be on all the time. How exactly do you get a SHORT TO GROUND in a brake light switch?

A short (circuit) in the MFC would cause that specific circuit to be on all the time (or off) depending on what circuit it is. A short (circuit) to another circuit could all kinds of things to happend including fuses blowing and/or a meltdown of wiring (fire).

Most likely there is a wire in one of the lighting circuits that has its insulation rubbed off and touching chassis ground which is a SHORT TO GROUND.

Have a trailer wiring harness? Start there first.

Very big difference between a short to ground and a short circuit.

 

[lesterl]

Stop lamp switch has 12v run to it as well as the MFC switch (shorts of which can and will pop a fuse)

 

[remauto1187]

Stop lamp switch has 12v run to it as well as the MFC switch (shorts of which can and will pop a fuse)

You obviously have little understanding of very basic electrical principles. When any Normally Open switch (including the brake switch) is actuated it is electrically shorted across its contacts, which is what it is electrically suppose to do. Electrically shorted (AKA Bridged) is VERY different from a Short To Ground which would indeed cause the fuse feeding that circuit to pop (electrically open). But explain to me how exactly it is even possible for a Brake Light Switch to get a Short To Ground? It isnt Possible. Vaguely possible to happen within a MFS assuming there is a terminal that is grounded that gets shorted to a 12vdc terminal due to a mechanical/electrical fault within the MFS itself.

I raise the BS flag on the Brake Switch Short To Ground theory. Not Possible.

 

[mbumgua]

Check for short to ground where rear wiring bundle rubs on back side of inner drivers side fender liner. Had one short out brake lights here. Took me several months to find it!

 

[lesterl]

Stop lamp switch has 12v run to it as well as the MFC switch (shorts of which can and will pop a fuse)

Perhaps I need to watch my punctuation.....

Stop lamp switch has 12v run to it, as well as the MFC switch (shorts of which can and will pop a fuse)

 

[lesterl]

And rema, you dont need to get nasty, what is your electrical background?