Hazard Warning Switch (MOT failure)

[Readit]

I suspect many Elan owners are now experiencing difficulty in getting their hazard warning switch to pass an MOT. After track rod ends this is probably the most likely item to go tits up just before the all important test, especially if the car has been standing. (assuming you keep the rusty wishbones at bay)

I have refurbished 3 of these and the secret seems to be in the 4 prong copper combs making correct contact without touching when they shouldn't. Many people seem to go straight in with a soldering iron and replace the diodes/LEDs but in my experience when you get the switch right all these miraculously start working again. A sign of a poor contacting switch is one winker only working when the hazard is on and only flashing at the winker not the hazard.

Cleaning and/or solder coating the tips of the copper combs can help contact, but as I said before the secret is in the alignment, some prong ends contact both in and out but the prong itself should not. The copper prongs are quite fragile so do not bend too much, (slightly concave to the outside is best) once a prong is broken the switch is kaput. Other things to watch are the two springs which zoom out when you GENTLY prize off the main cover (not switch front cover) There is also the "piece de resistance" a minute plastic prong with nipples at each end, this controls on/off in/out action and is also crucial and extremely fiddly. Clean, straighten gently and a small amount of vaseline on re-fitting seems to work. Holding everything in the right place while you push the two halves and three parts of the switch back together is an art. Do not apply pressure until all prongs are in the right place otherwise a bent back prong is the end (see above)

I was told replacement switch numbers were on wiki LEC and finally found them under "SWITCHCRAFT".
However they are following, if you can find switches in stock anywhere:

Genuine Lotus (Hen's teeth) B100M6019F (£128 at the breakers)

GM Part No GM 90213284 but these have a white triangle not red (for the purists, MOT testers not included)

These GM Part Nos are basically the same switch but with a modified front, it requires transferring your original Lotus front push button GM90213285 GM90316822 OPEL NO 1241649 (some say they may be available in Germany? - getting rare)

[clemo]

2'nded .
It is just usually a bad connection . As i also found last week prior the MOT .

[Readit]

Very true. Bad connections happen both inside and outside the switch so if cleaning outside contacts and connectors works for you, then great.

Elan health warning: only take the switch apart when all else fails to cure the problem.

[Rambo]

Rear brakes and emissions yes, but I've never ever had any problems with hazard switches failing MOT's. That's in 14 years and with 3 different SE's

Anyone else had this problem ?

[dapinky]

Rear brakes and emissions yes, but I've never ever had any problems with hazard switches failing MOT's. That's in 14 years and with 3 different SE's

Anyone else had this problem ?

I've had all 3 at various times, before addressing the issues causing them.

Hazard swith on the red car, first MOT after getting it.... borrowed one from Paul, and then replaced it with mine, which miraculosly started working.

Emmissions sorted by going closed loop.

Rear brakes just require cleaning and greasing regularly (and changing the prop valves).

[Readit]

This is the internal wiring diagram of a hazard warning switch it seems to connect almost every circuit on the car. I once took mine off for a refurb and when I refixed it, one winker worked when it was ON but the ignition lit up when it was OFF. Needless to say it needed another try. Unfortunately, you need to remove it, mend it then put it back to test so every time it is, start from scratch, until you get lucky or more experienced at the problems.

[gwiz22]

Hi Readit
I've just read your posts re: Hazard switch, and I am experiencing some issues with mine and hope you might be able to point me in the right direction. My hazards stopped working. While attempting to pull out the switch I managed to pull the front cover off it. Interestedly, the white inner plunger part of the switch, when pressed turned the hazards on. Great I thought, just have to pop the outer cover on then all will be well. Sadly, not to be. When the outer cover was clipped back on, it would not turn the switch off when pushed so the hazards stayed on all the time.

Giving up on the switch I purchased one off ebay. I was aware this was a reproduction of the the GM switch but thought, if it worked then great. However when I installed the repro switch, the ignition came on even though there was no key in. I then started the car thinking maybe the computer needs so re-initiate itself but when I turned the ignition off the engine continued to run for a few minutes before stopping.

So I'm at a bit of a loss. I feel I should I have a go at mending my original switch but if I mess that up I'll be truly stuffed and the available replacements don't seem to work either.

As you have dismantled a switch would you happen to know if my problem regarding the on all the time problem with my original switch is something that can be resolved in the internal workings of the switch?

Thanks and Regards
Graham

[GeoffSmith]

There was a picture of an eBay hazard switch (it looked like it had been modified) on FB but by the time I went back to compare it to a genuine switch, it has disappeared. I suspect that a connection has been made from the permanent live to the switched live which would explain your symptoms Graham. Could you post a picture of the connector side of the switch including GM part number please?

[Readit]

Hi Graham,

You will see my posts on this were made in 2005, I have since replaced my Elan and no longer have the problem but that may seem a drastic solution. The hazard warning switch is certainly a work of art and I have taken apart a broken one which I have,(photos attached) so you can see some of the problems before starting to fix it.

As far as the replacement you purchased on the internet, they are usually genuine GM parts made for a 1990 Vauxhall/Opel Carlton and had white lights instead of the red specified by Lotus. These should work as they are the same pattern but I have never tried one.

Back to repairing the switch: 1. Remove outer switch cover to expose white plastic switch beneath, 2. on the back (pins side) gently prize edges to release inset hooks to switch body whilst holding switch front and back to stop it springing apart.

parts of switch.pdf

3. When clips are free gently pull switch apart making sure not to lose two springs and a small white plastic tongue, all of which come out unexpectedly. 4 Tongue and springs will probably be gunged with old grease, carefully clean all parts,

5, The white switch button has eight copper prongs at the back which should be in good condition and clean, a light rub with fine wet and dry paper to all contact surfaces on the prongs and switch body is recommended.

6 Check all prongs for alignment, ends should contact when both on and off but the stalk of the prong must not touch either on/ off or when in operation. Putting the switch back together requires some touches of Vaseline to springs and white tongue.

prongs and contacts.pdf

7 Springs should be held into the white switch button with Vaseline whilst gently easing into the switch body with the white tongue already in position on in the main body of the switch. Ease the copper prongs into place without using force as a bent prong is the worst outcome. When the white switch body is in the right place, the larger end of the white tongue locates into the round hole at its base,

white tongue position.pdf

The springs and the tongue cause the on/off action, so if these are not properly located, the switching action will not work. The front switch body front can be replaced, this holds the white tongue in position. When the front switch body is clicked in place, the switch front can be added. If the switch mechanism operates properly it can be then checked for electrical operation either by testing the continuity of circuits as the wiring diagram, in both on and off positions, or replace switch in car and test insitu.

PLEASE NOTE in the attached photos, my broken switch is missing both springs which locate in the back of the white switch button, it also has a broken prong end attached to a piece of masking tape and the red warning diode is not attached at all. Hope all this helps.