Blowing fuse - source?

Submitted: Tuesday, Jul 26, 2005 at 13:49

ThreadID: 25065 Views:1910 Replies:10 FollowUps:4

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Moose

My 80 is constantly blowing the brake light fuse. Any suggestions on where to start looking for the problem?

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Reply By: flappa - Tuesday, Jul 26, 2005 at 13:57

Tuesday, Jul 26, 2005 at 13:57

The Trailer plug is often a source for blowing fuses.

AnswerID: 122122

Reply By: Well 55 - Tuesday, Jul 26, 2005 at 14:27

Tuesday, Jul 26, 2005 at 14:27

Sounds likr there is a short somewhere in the brake lights. and yes I would be looking at the tow plug first.

AnswerID: 122129

Reply By: Kiwi Ray - Tuesday, Jul 26, 2005 at 14:37

Tuesday, Jul 26, 2005 at 14:37

Also check the stop light bulbs as these can also blow fuses

AnswerID: 122135

Follow Up By: Moose - Tuesday, Jul 26, 2005 at 14:49

Tuesday, Jul 26, 2005 at 14:49

Please explain - what exactly would I be looking for with respect to the bulbs?

FollowupID: 377298

Follow Up By: Member - Jeff M (WA) - Wednesday, Jul 27, 2005 at 17:34

Wednesday, Jul 27, 2005 at 17:34

I had an intermitant problem (twice now!) with brake light globes being dicky. The fuse was not blowing but the lights would intermitantly stop working. I thought for ages there was a wiring fault but it turned out the globes were the problem, they were "half" blown. Weird I know, I pulled them in and out and used CRC and tried everything over a period of a few weeks, went and got a new globe and the problem was solved never to be had again.

A couple of months later, the othe side started doing it. (ah ha, I had it beat this time). I just changed the globe an it sorted it out straight away...

FollowupID: 377515

Follow Up By: Dan 1 - Wednesday, Jul 27, 2005 at 23:36

Wednesday, Jul 27, 2005 at 23:36

strange but feasible. The filament in a globe has a level of resistance which in turn creates heat when current flows through it Normally when they blow, the filament separates creating an open circuit.
It's quites possible that the coils of the filament could fuse together creating a bridge across and thus have hardly any resistance allowing more current than normal and in turn cause the fuse to blow

FollowupID: 377607

Reply By: Kiwi Ray - Tuesday, Jul 26, 2005 at 15:12

Tuesday, Jul 26, 2005 at 15:12

There have been times that I have found that the bulbs ( globes have broken internally and gone to ground also ceck the bulb holder.
You may like to check that the correct bulbs are fitted
Ray

AnswerID: 122138

Reply By: Diamond (Vic) - Tuesday, Jul 26, 2005 at 17:53

Tuesday, Jul 26, 2005 at 17:53

pull both your brake light globes out and replace the fuse.
get some one to depress the brake pedal and replace the globes one by one and at least you will know what side is causing the problem.
but as said above trailer pplugs are usually guilty.
cheers

AnswerID: 122156

Reply By: shaggy - Tuesday, Jul 26, 2005 at 22:25

Tuesday, Jul 26, 2005 at 22:25

mine blows stop lights if i have the headlights on, and then try to use the rear wiper. So i never use the rear wiper with the headlights on. Try that, it may be the same.
cheers

AnswerID: 122216

Reply By: muzzgit (WA) - Wednesday, Jul 27, 2005 at 01:31

Wednesday, Jul 27, 2005 at 01:31

If that doesn't work, try holding your tongue between your teeth whislt whistling dixie with your right foot in you left hand while reversing.

Does the trick for me !!!!

AnswerID: 122232

Reply By: Member - Collyn R (WA) - Wednesday, Jul 27, 2005 at 10:38

Wednesday, Jul 27, 2005 at 10:38

The most likely cause is an intermittant short circuit.

Failing that however, fuses can fail if they or the fuse holder has slightly corroded or the holding mechanism is loose. Then, the resistance so introduced causes the clips (or whatever) to heat up and thermally conduct that heat to the fuse itself - thus lowering the current level at which it blows. This is not uncommon particularly with older vehicles.
Trust this may help
Collyn Rivers

AnswerID: 122259