headlight woes 2a SWB

[bentleighboy]

Greetings all,
Yep its Sunday night, when all of the weekend warrior mechanics get to the end of their tethers and flock to the Collective Wisdom for advice.
Its like this.
Just completed a major refurb of the front end (firewall forward) of my 2a, and took out the radiator panel and all lights. I was careful to tag and number every connection so that it would go back the way I found it.
Ive also taken the opportunity to change from 7" sealed beam units to the Wipac Crystal lenses and H4 bulbs from Paddocks.
This is what I find:
Headlights won't work!
Sidelights ok
Blinkers ok
Both the headlights are on a good earth (to the black "common" wire. It is still pos earth)
When connecting the H4's to the battery direct , in their sockets, they work fine.
There is definitely 12.8 v or so from the earth to the neg terminal on Batt.
There is no V between the common terminal and either of the red terminals on the back of the socket.
No V either when turning on the headlights switch.
The battery is a new and charged Optima (which was present prior to the current problem)
So where is the problem??
The loom from where the headlight wires plug in , back to the firewall, looks ok as far as i can see it. Nothing broken, exposed, rubbing.

Does this mean a faulty ignition / light switch?? And how to test the little sod??

Many thanks for your sage advice,

BB. [bawl]

[101 Ron]

See if you have volts from one of the live wires from the plug or connector with the head light switch on for the globe directly back to the battery terminal earth (positive).
That will show if there is a problem with the earth wiring.
Don't test using chassis or plug/ terminal earth.............Go back to the battery terminal post for earth.

Another easy thing to check is the fuses as you could have easily flashed a wire to earth without realising it and blown a fuse..

[bentleighboy]

Yep there is def 12+ V from the black terminal (common, or "earth") back to the neg on the batt.
Fuses all clean and good.

As far as I know there are no headlight relays on Se. 2's ...?




See if you have volts from one of the live wires from the plug or connector with the head light switch on for the globe directly back to the battery terminal earth (positive).
That will show if there is a problem with the earth wiring.
Don't test using chassis or plug/ terminal earth.............Go back to the battery terminal post for earth.

Another easy thing to check is the fuses as you could have easily flashed a wire to earth without realising it and blown a fuse..

[JDNSW]

Assuming the wiring is original.... there are no fuses or relays in the headlight circuit. There may be a burnt out wire - look at the wiring loom for heat damage, especially the one running along the mudguard to the front lights.

Most likely either a faulty connection, but since neither beam works, if I understand correctly, this narrows it down. It has to be either the connection at the headlight switch (can't be battery input to switch as sidelights work) or the connection to the dip switch on the floor - according to the wiring diagram there is one connector along this wire.

If it is not a faulty connection, it will be either the headlight switch or the dip switch. Because of its location (in the dirt and mud on the floor) the dip switch is likely to be at "end of life", although cycling it a few times may work. There are two types fitted, although I think yours should have one with a rectangular base - but they are interchangeable, and any floor dip switch will work. By this time the main switch is likely to be well worn, and if higher wattage lights have been fitted is likely to have been damaged by excess current. These can be disassembled, and it is likely to be repairable by someone with a bit of ingenuity.

Use a test light or meter to check for voltage starting from the switch to find just where the issue is. (when removing the instrument panel disconnect the battery, reconnecting it after pulling it out - too easy to short something getting it out)

[pop058]

Greetings all,
Yep its Sunday night, when all of the weekend warrior mechanics get to the end of their tethers and flock to the Collective Wisdom for advice.
Its like this.
Just completed a major refurb of the front end (firewall forward) of my 2a, and took out the radiator panel and all lights. I was careful to tag and number every connection so that it would go back the way I found it.
Ive also taken the opportunity to change from 7" sealed beam units to the Wipac Crystal lenses and H4 bulbs from Paddocks.
This is what I find:
Headlights won't work!
Sidelights ok
Blinkers ok
Both the headlights are on a good earth (to the black "common" wire. It is still pos earth)
When connecting the H4's to the battery direct , in their sockets, they work fine.
There is definitely 12.8 v or so from the earth to the neg terminal on Batt.
There is no V between the common terminal and either of the red terminals on the back of the socket.
No V either when turning on the headlights switch.
The battery is a new and charged Optima (which was present prior to the current problem)
So where is the problem??
The loom from where the headlight wires plug in , back to the firewall, looks ok as far as i can see it. Nothing broken, exposed, rubbing.

Does this mean a faulty ignition / light switch?? And how to test the little sod??

Many thanks for your sage advice,

BB.


Yep there is def [B]12+ V from the black terminal (common, or "earth") back to the neg on the batt.
Fuses all clean and good.

As far as I know there are no headlight relays on Se. 2's ...?

Is it me or does this not sound right ??

[bentleighboy]

Fixed it.

It was in fact the floor switch, a strange time for that to fail. Good call whoever suggested that. New one about 11 quid.
I also found Teri Ann Wakemann's website good, she explains the connections on the back of the rotary switch, and where to find the "lights power out" terminal. Its the one on the bottom, far right when you're sitting in the car looking down at the back of the panel which you've pulled out of the bulkhead with all the wiring still attached.
SO that was live with lights switched on.
"Power in" wire to dip switch then identified, also now live.
This terminal is the one of the three, on its own.
The other two sitting side by side, are high beam - low beam (alternating , doesn't matter which)

Also had fun fixing all the ****ty wire joins behind the dash panel (twisted with sticky tape etc from previous owner) with solder and shrink tubing.

The Wipac clear lenses / H4's look good and seem to shine a treat.

Thanks All![bigrolf]