brake light stuck on.

[leggy7]

Hi
Have an issue with the other half's 1997 2.7 Maverick,

It blew a fuse, well actually melted the fuse and the holder, the other day, and have rigged up a bypass using an unused fuse space but the lights are still staying on, have looked at the pads on the brake switches, and there are "dimples" for want of a better way of describing the pad, but put some metal over them but the brake lights still on,
could the power surge blown the switches, does the brake circuit actually contain a relay, or would it be a question of changing both the switches and the pads on the pedal?

or are we into the realm of something totally unconnected happening

many thanks
lee

 

[Banshee]

Hi
Have an issue with the other half's 1997 2.7 Maverick,

It blew a fuse, well actually melted the fuse and the holder, the other day, and have rigged up a bypass using an unused fuse space but the lights are still staying on, have looked at the pads on the brake switches, and there are "dimples" for want of a better way of describing the pad, but put some metal over them but the brake lights still on,
could the power surge blown the switches, does the brake circuit actually contain a relay, or would it be a question of changing both the switches and the pads on the pedal?

or are we into the realm of something totally unconnected happening

many thanks
lee

That sounds a little weird :doh

How did it melt the fuse?

 

[Lazy-Ferret]

When you say Brake lights, do you mean the big red ones on the back of the car, or the Brake warning lights on the dash?

The switch for the big red ones is on the brake peddle, the switches for the others are on the Hand Brake, Break Fluid reservoir, the ABS system, and of course the wear sensors..

 

[Lazy-Ferret]

That sounds a little weird :doh

How did it melt the fuse?

If someone replaced the fuse with one of those cheap spade fuses like Halfrouds and the poundshop sell, the metal spades are a lot thinner than the ones Nissan use, so do not make as good a contact as the original ones. This creates a resistance in the connector, which then gets hot and melts the holder and fuse.

I had to go through my spare fuses, and throw a load away as when you looked at the spades they were noticeably thinner, and some even had a layer of an oxide of some sort or another corroded across them. That was after one burnt the fuse holder out on my Spot lamp Relay...

The problem is, because the fuse sits in a shroud on most holders, meaning the body is supported, it's not immediately obvious that the contacts are not tight.

 

[leggy7]

hi all, it is the spade fuse which totally melted, and took the fuse holder with it, other half states that there was thick acrid smoke coming from the dash, so lucky that the whole car didnt go up.

it is the brake lights at the rear of the vehicle,
thanks in advance
lee

 

[Lazy-Ferret]

A quick look at the Service manual, and it looks like the peddle switch feeds into the ECU, and the ECU then controls the lamps, but no obvious external relay...

Looks like you will need to dig a bit deeper...

If you down load the workshop manual, the bits you need to look at are:-
EL page 48
EC page 400 - 403

 

[Blocky10]

If you've bypassed the problem area with another fuse and the brake pedal switch feeds to the ecu, it may be an idea to disconnect the battery for a while to reset the ecu. It maybe confused (sorry :lol)

 

[rayf3262]

there are two switches for the brake light, one tells the ecu you have your foot on the brake and the other operates the brake light in a conventional manner.
See page EL-48.

 

[jims-terrano]

Have you got a towbar fitted? Could be a short in the towbar wiring.

 

[leggy7]

hi was thinking that it could be in the towbar wiring, will have to take a look, ( made the mistake of letting the son in law hook it up:doh) noticed that the rear brake lights bulbs were on,when they called me to say that they were having a problem,will check the wiring and if that seems okay think will have to try the switches, but will wait to see if disconnecting the battery makes any difference

 

[jims-terrano]

So did the problems occur as the towbar had been wired in and everything was fine before the towbar?
Wonder if they used a bypass type wiring kit.

If the problem has occurred due to the towbar wiring then trace all the wiring and put it back to standard again.

Modern cars normally need a fancy bypass type wiring kit due to all the bulb failure sensors and stuff. Our trucks are blessed by being old fashioned reliable wiring, towbar sockets simply splice in with the need for relays and battery feeds other than the carvan supply.

 

[rayf3262]

Here is the section brake light circuit you need to fault find:

 

[leggy7]

thanks all
left the battery disconnected for a while and that has seemed to have done the trick with regards to the getting the lights to work normally.
thanks for the advice and help

 

[Blocky10]

Good news :thumb2

 

[leggy7]

well i thought it had worked, work ok twice then light stuck on, have tried 2 new switches and every time i fit them, they work once, and then stay on,
any ideas, could it be surge blowing the switch, but have taken one apart nd there doest seem anything to blow..
help

 

[Banshee]

well i thought it had worked, work ok twice then light stuck on, have tried 2 new switches and every time i fit them, they work once, and then stay on,
any ideas, could it be surge blowing the switch, but have taken one apart nd there doest seem anything to blow..
help

I'm going to go with towbar wiring short :thumb2 Give it all a look

 

[solarman216]

About right I think a short permanent live to brake light is most likely, it has nothing to do with the switch, Rick

 

[leggy7]

hi all thanks for the advice, the strangest thing has happened, whilst messing with the switch i managed to blow the fuse, but replaced the fuse and hey presto everything works !!!!!!!!!!!!!!!!! im sure it was not the fuse as had tried different fuses....
anyway have checked all th other electics and they work fine so.. thanks again:thumbs:thumbs:thumbs

 

[jims-terrano]

I'd still be inspecting your towbar socket

 

[solarman216]

hi all thanks for the advice, the strangest thing has happened, whilst messing with the switch i managed to blow the fuse, but replaced the fuse and hey presto everything works !!!!!!!!!!!!!!!!! im sure it was not the fuse as had tried different fuses....
anyway have checked all th other electics and they work fine so.. thanks again:thumbs:thumbs:thumbs

I would say you still have a problem and still most likely with your van socket/wiring, when the fuse blew it will have burnt a bigger gap tween the two wires that were giving the problem, so for the moment your problem has gone away but it will return probably when the offending bit gets wet, Rick