Couple Electrical Issues - 04 TD5 Defender XS

Noticed a couple minor (I think) electrical issues while out laning today.

First of all the handbrake light ((!)) is flickering on or stays on even if the handbrake is off - I assume this is an earth issue? Not really bothered if the light works or not, I just don't want it flickering its pretty distracting! Where is the wiring for this?

Second one is the Difflock light does not illuminate when engaged. The difflock does however work I have checked. How can I fix this? I quite like that light!

Thanks
Josh

Handbrake light could be low brake fluid warning

Kwakerman said:

Handbrake light could be low brake fluid warning

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I'll check that but unlikely as it just had braided lines fitted by the garage and bled, so one would assume its topped up....

I didnt know a Defender had such a warning system!

bankz5152 said:

I'll check that but unlikely as it just had braided lines fitted by the garage and bled, so one would assume its topped up....

I didnt know a Defender had such a warning system!

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Unless they have left a union loose!
If your cap has a couple of wires attached then that is for the float switch

Dont think so, braking has been fine, driving 100miles had no issues. Though I will double check tomorrow night.

It has got the wires on the cap, never thought that would be for a warning system lol

Both the handbrake switch and the brake fluid level switch operate to earth. That is an earth condition is applied by the switch to activate the circuit, so it's unlikely to be due to a missing earth. It's more likely to be due to as has been said, the fluid level switch activating or the wiring, particularly to the handbrake switch having been damaged by rubbing the insulation through allowing a "flickering" short to earth operating the circuit instead of the switch.

Regarding the "diff lock" light, there are four things to consider in any simple circuit such as this.

1. Power supply. Is this the 12 volts, as expected? If not, check the fuses.
   
2. The light source. Whether a bulb or LED, is the light working when test conditions are applied? If not, replace the bulb.
   
3. The switching device. Does the switch apply the correct electrical conditions when operated under test? If not, replace or repair the switch. If the switch cannot be operated under test, then it might indicate that it is mechanically faulty.
   
4. The wiring. If the above conditions all appear to be correct, then it's a reasonable bet that the problem might lie in the wiring. Without getting too clever with test meters and such, a check will probably eventually result in a physical and visual check of the wiring between the earth and the switch, the switch and the bulb, the bulb and the fuse.

Td5 are prone to flickering brake fluid light, often caused by corrosion on the contacts inside the yellow cap on the fluid reservoir.
Pull seal out of cap and clean contacts with sand paper.
Diff light not working could be the switch not screwed in far enough into the transfer box, as the diff lever completes the circuit on the switch when put in locked position

Cheers guys. I shall start with the brake fluid cap, then check the handbrake wiring. It can't be a blub as the TD5 uses an LED cluster, you can't change individual bulbs.

Where can I find the difflock switch? Is it best going from underneath, through the central inspection panel or the top of the transmission tunnel?

These are both problems I've had.

The brake warning light flicker was hard to chase down. Eventually it turned out to be the brake fluid cap itself. There's a kind of pot on the underside of the cap with a little hole in the bottom. I reamed it out a little and solved my brake light problem. It was taking too long for the fluid level to equalise between the inside of the pot and in the main fluid reservoir. With a slightly larger hole, the fluid can get in and out more quickly, so it doesn't put the light on when going downhill or braking heavily as it was before.

The difflock light switch was just not screwed in far enough in my case. As the threads were full of corrosion and dirt I had to take it out and chase them out. this also gave me an opportunity to test it with a meter and check that it was making and breaking the electrical connection satisfactorily (which it was). If you screw it in too far it can interfere with the operation of the difflock mechanism. With the gearbox in situ it's probably easiest to get at with the transmission tunnel off. This can be quite an exercise in itself as all the crosshead screws which hold it down are bound to be corroded!

Thanks Brown, I'm not pulling the tranny tunnel off, all of those screws are badly corroded and with the A/C in the way it will be a bloody nightmare.

Is it worth just replacing the cap?

I think with a bit of dexterity you can get to the diff lock switch from below and wind switch in a bit with a stubby spanner

That's just my experience by the way - I merely mention it because it's an aspect of the brake fluid cap's function that tends to get neglected. I see caps on their own are £10-20 (or more) so to my mind you might as well have a fiddle with it.

I shall have a look this eve, thanks, very useful info.

Checked the brake fluid, it was actually a little low, well not low, it was just under half full. So I have topped it up, may solve the issue. If not ill clean it up as described above.

Not doing anything else tonight as the landy is muddy and wet. Garaged now so ill have another look tomorrow.

Mine did the same with the handbrake. It was the cap on the expansion as mentioned and then a dodgy/stickig switch on the handbrake. Disconnecting the handbrake wire solved it to test. A bit of electrical cleaner and its been fine since

Cheers. Going to have a quick drive around tonight, see if its ****ed off

Drove around for about 30 mins, fast road, bumps and some braking. Lights gone! Ut appears 110 doesnt like anything but a full brake fluid tank!

Cold and dark outside so ill investigate the difflock situation on the weekend.

mine only likes the expansion tank full too

Got to love em ay?