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I have a 1996 (mk IV) 1.8 diesel Fiesta but the handbrake warning light does not come on the dash. Other than a blown bulb what else could it be? If it is likely to be just a blown bulb, how do I get to them? Thanks in anticipation! Mark.
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Check the plug going to the warning light switch on the cap of the brake fluid reservoir.
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Mike Farrow
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Is there not a switch under the brake lever.
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There are two switches;one a microswitch under the handbrake and the other a level switch in the cap of the master cylinder-the first triggers when the handbrake is not right down and the other when the fluid is low.If power is getting to both these switches,then bulb failure is the likely reason.
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Bit of an update - I tried all the fuses in the interior and engine fuse box - none had blown. I have taken the connector off the top of the brake fluid reservoir and it was full of rust, so cleaned that up and gave it a good dose of terminal cleaner. Still no brake warning light on the dash. Got an electrical tester and found there appears to be no live feed coming in to the connector. I went further back down the wires from the connector and tried there for a live but still couldn't get anything. Any ideas???
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its not a + feed its - live feed is on rear of dash as these are negative switched bulbs with permanent positive,when ignition on.
check the switch on rear of handbrake they have a habit of either coming loose or losing the connector,check the fluid level light by removing the cap light should come on if nothing else wrong ie bulb gone
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Steve
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found there appears to be no live feed coming in to the connector.
With the ignition on there should be! Therefore you've got a blown bulb.
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Mike Farrow
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sorry - can i just check (i don't understand electrics at all) - if I've got a blown bulb in the dash then that would cause me to have no live feed coming into the connector on top of the fluid reservoir - is that correct? Thanks for all your help.
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yes that is correct but its more likely that the bulb has wiggled round and needs turning back,the only problem is that you may need to take off the steering wheel with its airbag to get the speedo head display out,post back if you do as there is a set procedure that must be adhered to in this case.
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\"a little man in a big world/\"
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Thanks oldman. I started to remove the speedo display the other day thinking it may be a blown bulb but gave up when I realised you had to get underneath the car and disconnect the speedo cable (according to a Haynes manual). I would have had clear access to the speedo area once the cable had been removed so don't think I'll have to remove the steering wheel. Seems a lot of aggro just to change a bulb!
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Presumably,the float switch and handbrake switch turn on the bulb by connecting to earth;therefore if there is no power to them either a bulb or supply problem.
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Presumably,the float switch and handbrake switch turn on the bulb by connecting to earth;therefore if there is no power to them either a bulb or supply problem.
To an extent, this depends *how* the OP was measuring there was no live feed at the handbrake or float switch.
If the OP was using a higher power/lower resistance test lamp, it is possible that the bulb wouldn't light because all the voltage drop was across the small bulb in the dash.
If, however, the OP was using a high resistance device, like a DVM, say, then the absence of a live feed would point to a break upstream, and possibly a broken bulb in the dash.
Number_Cruncher
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If, however, the OP was using a high resistance device, like a DVM, say, then the absence of a live feed would point to a break upstream, and possibly a broken bulb in the dash. Number_Cruncher
holy batman robin what is all theses words to the man in the street??????????/
well op means original poster
and dvm means digital voltmeter
i think what number cruncher is trying to say but cant think of the word is that the "bulb" has gone it runs on 12 volts any source will show this from an indicator bulb to a headlight bulb it might be dim but the source light will be there
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"a little man in a big world/"
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Why not just earth the wires(possibly with another piece of wire) and see if the bulb lights up-if you're not sure which side of each switch is earth,do both.
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No, Oldman, I was saying almost the opposite.
If the dash bulb is OK, and you test with, say a headlamp bulb it might not light because you would have the two bulbs in series, and most of the 12V would be dropped across the small, higher resistance bulb in the dash.
Whereas if you test with another high resistance device, like a DVM, most of the voltage will be dropped across the tester, and it will therefore read correctly.
The reason I posted my original post is that I have seen mechanics (and once or twice, myself too!) be misled by using an inappropriate test method for the particular circuit. In this respect, Peter D's favoured method of measuring current rather than voltage is probably more robust.
Sorry if my use of technical language and the odd TLA bugs you, but it's not going to change! If the OP has a poblem with the term DVM, for example, then he/she is free to ask.
Number_Cruncher
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sorry Number_Cruncher my point was that some people might not know what a dvm is ,it doesnt bug me at all.:)
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\"a little man in a big world/\"
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In case anyone is interested I've just found out what the problem was. One of the 3 wires that attaches to the top of brake fluid reservoir had broken in half, the reason I hadn't seen it earlier was because it was quite a way down at a point where all 3 wires are encased in sleeving. So the bulb on the dash was OK in the end. Thanks for all your suggestions though. Mark.
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So why didn't h/brake operation trigger it or have you a second fault??
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Good question and one I don't know the answer to. I work for a coach company and fortunately we had an auto-electrician at our depot today - he found the damaged wire, repaired it and its working now, thats all I know!
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So why didn't h/brake operation trigger it or have you a second fault??
jc2, Ford have this weird arrangement whereby the bulb is connected on one side to ignition in the dash and then the other side to the reservoir cap. The reservoir cap has two other wires, one for the reservoir switch earth, and one going to the handbrake, the latter being pernamently connected. So it's a fairly crude warning system to tell you the cap isn't connected up properly if you don't get a light on with the handbrake.
I'm surprised you found a broken cable in sheathing. Was it rubbing or flexing against something? Anyway I suppose it doesn't really matter. Glad you got it fixed!
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Mike Farrow
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Yes Mike - apparently it had become squashed under something else which caused the broken wire.
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>>,it doesnt bug me at all.:)
Ah!, good, good! As you're clearly a man of robust and strident opinion, I had feared that you would wish me to be "lanced like a carbuncle" for my crimes against clear English!
Cheers,
Number_Cruncher
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