Check/adjust brake lights, reversing lights and panel warning lights

Continuing to work my way through the MOT-essential items I need to finish checking all the lights.

Reversing lights
Reversing lights- select reverse- turn on ignition and....??
Well the switch is obviously working as one light came on- however the rear LHS did not!

Obstinate reversing light!

To check the reason for this you need to remove the fragile and newly painted delicate plastic shield! Still its only 4 screws -harder to replace than take off.

4 screws holding rear light cover panel

 Lights are then visible from behind. In my case they were very stiff and I was loathe to force them... as usual there's no mention of these basic questions in the WM. They are however a simple anticlockwise twist-to-release

Dirty and stiff connections to rear of lights

 Interestingly the bulb was actually fine- if I hooked up a 12V supply it came on nicely- however not in the holder! As usual the problem is corrosion and poor contacts. I removed the spade connectors and cleaned all contacts, applied a little DE grease and refitted...

The corrosion had made one of the connectors so brittle it just snapped.

broken connector

I crimped on a fresh connector and rebuilt- Both rev lights now working! .. I guess it also means that it would be a good idea to strip, clean and replace contacts on all lights both sides.... well eventually maybe! For the time being I will leave them since they are all so tight that removing them is likely to lead to breakages.

I also needed to check the brake lights- and here I got a surprise! I have already checked the rear tail lights and they were fine- however I now discovered that in fact the brake lights were permanently illuminated owing to incorrect brake switch adjustment! This means I don't actually know that the tail lights are working!

Anyway adjusting the switch is surprisingly simple.

Brake light terminals

I removed the brakelight switch by twisting the body anticlockwise and pulling it out of the plastic mounting grommet in the pedal box. The button was then free to spring out. Connecting a meter showed that this gave continuity between the switch terminals.

Whilst the switch was disconnected I turned on the sidelights to check that both tail lights did in fact work... phew, they did!

Brakelight switch removed- button springs out- contacts closed, press it in and they are disconnected

I could then gently re-insert the switch keeping an eye on the meter. This showed the switch was closed and the terminals connected (lights on), but as the button contacted the brake pedal shaft it was pushed in to the point where continuity was broken (lights off). I then pulled the switch backwards and forwards a few times to make sure it was located just at the point where the contacts were open but just about to close, and then twisted it 1/4 turn clockwise to lock it in position. Depressing the brake pedal then caused the switch plunger to extend and the contacts to close which should turn the brake lights on. I still can't see the brake lights at the same time as operating the brake pedal, but by connecting an ammeter in series I was able to show that depressing the pedal did at least cause a current flow which ceased when the pedal was released. I am assuming this means the lights are illuminated when the pedal is depressed. I need someone else to check that I have two lights!

Reading the forum suggests that brake lights (possibly all lights) are best replaced with LEDs. This produces more light for less power (i.e. heat) and sounds like an excellent idea to avoid melting the fittings and reduce strain on the battery and loom. I will put this on the list as something to work through when I get a chance... Probably when I clean all the contacts.

Dashboard indicator tell-tale
The final light problem I had identified was that the Right hand turn tell-tale bulb didn't come on with the indicator.

Rhs tell tale panel

 At least I have the dashboard off already so its easy to get at the switch mounts which form a battery of connections behind the warning light panel..

Bulb holder bodies at rear

Each is a simple anticlockwise twist to release.

Rear of light battery after removing bulb holder. Note twist lug locating slots.

The bulb and holder can then be pulled forward. The bulbs in these lights are simple capless 3W items. They just pull out and push in.

Tell tale bulb holder

I pulled this one out and tested it... yes you've guessed it was fine! 

Capless bulb just pulls out.

The contacts on these bulbs are just bent wires and they seem to have been folded too closely to the bulb and weren't making contact inside the bulb holder. This is probably a casualty of my removing and pulling on the dash whilst I was trying to sort out the pedal box. I pulled them outwards a little, cleaned and refitted the bulb to its holder and yep; tell-tale now telling tales!

I now need to check all the earthing points are bolted tight and then I can refit the dash, under-dash panel and seat... definitely getting there!

Note added- I forgot I have fog lights! Testing these revealed that they do work (only when headlights are on as expected) but only one bulb was illuminated. This meant a strip down of the LH light cluster and this time the fault was a blown bulb. As in all these holders the live contact is insulated and protected (seems to stay quite clean) but the Earth is not insulated and showed obvious corrosion, so I decided to clean up and grease the contacts to the bulb holder anyway. Once more the uncovered earth contact had become so brittle that it snapped when it was removed. I therefore fitted anew terminal on a fly lead to make sure it reached. This seems to be a common occurrence in these rear lights and I suspect all the earth contacts really need to be replaced.