'BRAKE' light not working

R

rp61973

Member
The dashboard 'BRAKE' light does not work when I pull the handbrake up. To date I have checked the following:

(1) Bulb - OK. This illuminates when I remove the top from the fluid reservoir (as it should to warn of low fluid level).

(2) All 4 brake pad leads are plugged in correctly. I have taken all these off and have squirted them with Servisol before replacing them.

(3) I have taken the section of warning light earth circuit apart in the engine bay (adj inner wing and on both sides), cleaned with Servisol and replaced.

(4) I have taken up the console to check the handbrake swith works - I have bridge the switch contacts to check all works OK - still not light on.

(5) I have taken the trim out of the boot, cleaned the bullet connectors where the rear pads connect to the earth circuit. Still no light.

I will now need to get a power source, a test bulb, lots of long wire and run around this earth circuit and find where it is defective. Bah!

Any other ideas??
 
I can't see the text to this post (again) but check the bulb & if that is o.k then the switch behind the handbrake lever probably needs screwing out a little which entails taking the transmission tunnel console off.
 
The handbrake switch is also the test for the pad warning light circuit, in other words when everything is working as it should it proves all the pad sensors are working as well as the handbrake switch. Go to the handbrake switch again and see if you have a supply to it. If so then check the earth from the switch. If you have supply and earth the switch is faulty. If you have no supply at the handbrake switch you'll have to trace the circuit back from there until you find a break in it. (It's a series circuit, so any breaks or disconnected pad plugs will stop it working)

Disconnect each pad plug and using a continuity tester make sure the two contacts on the loom do not have continuity, and the two contacts in the plug on the pad, do. It must be a break in the circuit somewhere, but it won't be a short to earth.



Edited By harveyp6 on 1212443906
 
Can we combine our brake circuits? My brake light hardly ever goes out, despite everything being OK! :(

Phil.
 
I thought the handbrake switch completed the earth circuit only and therefore would not have a +ve supply to it?
 
For this light to work you need the connections to be OK on top of the brake fluid reervoir and all the brake pad sensors to be connected correctly.
If you have access to a wiring diagram, you will see that the earth path goes through the handbrake switch, then through all four pad plugs before arriving at earth.
On my car it turned out to be a broken wire where it entered the rubber plug on the front suspension leg. The outer sheathing looked ok, but the wire itself had broken off inside.Took some finding!
One thing you could try is diconnecting the leads to the pad sensors, under the bonnet at the front, and behind the boot panel at the rear, and connect both black with white trace wires using a bit of cable. If this turns the light on, then reconnect the leads to the loom one at a time. If the light then stops working after connecting one, you at least know where to look!
MainFrame
 
Hi Mainframe and many thanks for the guidance. That sounds like a very systematic and sensible way forward. I will find myself a very long piece of wire at the weekend and do my best Columbo act! Paul.
 
mainframe444 said:
If you have access to a wiring diagram, you will see that the earth path goes through the handbrake switch, then through all four pad plugs before arriving at earth.
Click to expand...
the live supply actually goes through all four pad sensors, THEN through the handbrake switch to earth.
 
<<Quote>> Hi Mainframe and many thanks for the guidance. That sounds like a very systematic and sensible way forward. I will find myself a very long piece of wire at the weekend and do my best Columbo act! Paul.

You do not need a long piece of wire, just four little ones! At each connection point disconnect both black/white wires and connect the two wires together using your little piece of wire.
MainFrame
 
[/quote]the live supply actually goes through all four pad sensors, THEN through the handbrake switch to earth

Mr Pedant here......
Just checked the wiring diagram, the supply for this light comes from Fuse 19/20, passes through the BRAKE bulb in the dashboard then EARTHS either through the brake fluid level switch, or all four pad sensors then the handbrake switch.
Mainframe.... now counting rivets!



Edited By mainframe444 on 1212557215
 
Right, I have checked the front pad sensors, no problems there. I earthed each of the returning pad leads to confirm connectivity. I have narrowed it down to either the rear sensors or the hand brake switch (although I have checked the handbrake switch). I have a nasty feeling there may be a break in the black/white wire linking the front and rear circuit. According to the wiring diagram there is a pin connector linking this wire. Would be a wise place to check - does anyone know where this connector is located???
 
Mainframe, I used a slightly modified version of your test but earthed the front pad return lead in turn to check continuity across each pad sensor with a temporary direct connection to earth, instead of the short wire arrangement. This way checks each sensor as opposed to eliminating it from the possible fault. The reason being is that I did not have a piece of spare wire late last night!
 
Phil,

Re your BRAKE light remaining on. Have you checked the condition of the little cork float that sits in the fluid reservoir lid? This float can perish and become saturated with brake fluid which in turn prevents it from floating and keeping the BRAKE light warning circuit broken.

I had a similar problem and also took the opportunity to prise up the circular section of the lid with the contacts inside (snaps out) and clean the contacts. I replaced the old natural cork float with a modern synthetic cork out of a wine bottle (hic):p. I found I needed to cut the cork down slightly in length to enable it to fit on the metal shaft between the retaining washers. I removed the floating retaining washer at the bottom end first by squeezing the crimped end back true with some big pliers and slid the new synthetic cork on the shaft up to the circular static washer. I then replaced the floating washer at the bottom and recrimped the shaft to secure it on.

The new float works great - the warning light system is now a little more sensitive to fluid loss than before as the density of the synthetic cork is higher relative to that of the old natural cork float. The effect here is that less fluid needs to be lost before the fluid is unable to support the weight of the float and it then drops and energises the warning light. Can't be a bad thing - and ensures you keep your brake fluid level topped up!
 
rp61973 said:
I have a nasty feeling there may be a break in the black/white wire linking the front and rear circuit. According to the wiring diagram there is a pin connector linking this wire. Would be a wise place to check - does anyone know where this connector is located???
Click to expand...

from memory, I would hazard a guess at the driver's side footwell area, the loom which runs to the back of the car runs down here and along the edge of the driver's side floor. If you look towards the top of the panel to the right of the driver's foot, you can see where the loom goes in, and there are a number of connections here. Worth a look!
MainFrame
 
Hi Mainframe and many thanks. I tested the rear pad sensors last night and found the rear nearside sensor to be open circuit. The remaining circuit to the handbrake switch is OK, thankfully as is the wire from front to back. I lifted the hatch covering the diff mount in the boot (where the wire goes to the pad sensor plug) but no clues there - all seems intact. I will need to jack the beast up at the weekend and take the pad out to see what the problem is. I will test the section of wire between the bullet connectors and the plug on the base unit first.

Happy days! :laugh:
 
My brake light switch also does not appear to work although the circuit appears OK as the light came on once and I traced it to low brake fluid. When I topped it up with fluid, thelight went out. The previous owner told me the hand brake light switch used to work but the car had little use in the nine years before he sold it to me. The Rover repair manual tells how to remove the centre console,etc but I am having problems getting the gear change knob to come off. (It is a 3500S ) I am frightened to use too much pressure in case I damage the gearbox. The lever is the usual chromed shaft and it is flared like a trumpet at the top and the knob sort of sits on it. has anyone else had this problem? Thanks.
 
Classicus, I believe it does unscrew but it may be a little stiff as the knob cuts its own thread when it is screwed on. I have a spare standard knob I can send you in the post if you have problems. It is in good condition, but the white numbers would need to be repainted with a fine artist brush (as probably they all do).

The above sounds a little like something Finbarr Saunders from Viz would chuckle at. The words 'stiff', 'knob' and 'screwed' all in a single paragraph! Fnaar Fnaar!!
 
The gear lever knob has a thread insert .The collar below acts as a locknut ,it has 2 flats for a spanner. Loosen the collar and your knob will come off in your hand

(another Finbarr Saunder's reference ?)
 
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